FIELD NOTES: THE YELLOWSTONE LOOP

FIELD NOTES: THE YELLOWSTONE LOOP

Test Pilot Sean Jansen grew up as a surfer in San Clemente, but every summer his family pointed the car inland. His dad was a devoted fly fisherman, his mom loved the national parks, and a road trip to Yellowstone when Sean was eight years old set the course for the rest of his life.

Those trips kept pulling his family back until they eventually bought a house in Montana. After college, Sean followed. He fell hard for fly fishing, built a career writing about it, and today makes his living as a guide in the park.

Sean Jansen kneeling in a clear river, releasing a trout
Sean JansenGuide, writer, fly fisherman. Three decades in the Greater Yellowstone region.

Yet for all those years in Yellowstone, Sean had mostly seen it the way nearly everyone does: from the road, and in summer.

“With my job and with most people that visit the park, we are chained by the road systems in Yellowstone. But little do most know that over 90% of the park is wilderness, meaning that you need to get out of your car to really see and experience it.”

Sean Jansen

The Yellowstone Loop expedition was his answer. It is a self-supported, roughly 292-mile circumnavigation of the world’s first national park, traveled through the backcountry one quarter at a time, one season at a time. Spring, summer, and fall on foot with a pack. Winter on cross-country skis, towing a sled of gear across the final stretch where the trails give out and only unplowed roads can close the circle. Elevations run from 5,000 to over 11,000 feet. Temperatures, from 95 degrees down to 30 below.

As Sean completes each leg this year we'll be tracking his field notes written from the trail. Read his latest dispatch below.

Next up: Fall. The northern range, 76.4 miles planned. Sean sets out September 12th as the bison and elk rut takes over the landscape. His field notes will appear right here, at the top, when he’s off the trail.

Field Note 02 · Leg complete · Latest dispatch

Summer

On trailJuly 17–25, 2026
SectionSoutheast
RouteThe Thorofare to Yellowstone Lake

Words and photos by Sean Jansen

Sean standing on a steaming thermal area overlooking forest and a distant lake
07.17.26 · 9:48 AMDay one of the summer leg.

I was fried. I had been going for nine days and had walked well over 130 miles of mountainous terrain. It had been splendid as well, with sweeping mountain vistas, teeming trout streams, and an abundance of wildflowers and plant life. But I was tired and ready for some town food and to dry everything out. I had been rained on nearly every day of the trip, and the constant need to have a campfire each night to dry out my shoes was taking its toll on my feet, now nearly limping as I inched closer and closer to my van parked at the trailhead.

Mist rising off a lake below a forested ridge
07.18.26 · 7:34 PMAnother wet evening in the backcountry.

This final day of the summer section, I was walking along the eastern shore of Yellowstone Lake, the largest high alpine lake in North America. With over 140 miles of shoreline, it boasts habitat for all life in this park. But, for whatever reason, I had yet to see anything. Birds of prey flew overhead, trout sipped insects on the surface of the water, and deer would scurry about the forest upon my arrival, but nothing by way of bear, wolf, or even bison: the three most infamous creatures of the park and those I had been looking forward to seeing.

Sean walking the sagebrush shoreline of Yellowstone Lake
A cedar waxwing perched on a bare branch
07.23.26 · 11:05 AMYellowstone Lake’s eastern shore, and a cedar waxwing from day one.

For over 130 miles of hiking, I was in their presence, with scat and prints abound on the trail. One trail in particular had 43 scat from grizzly bear in just five miles. That’s an incredible density, and yet their physical presence was still absent. My routine every day of this trip, whether it was spring, summer, or the upcoming fall section, was to hang my food each night in a tree to keep it out of reach of bears while I slept. And not just food, but anything with an odor that’s not natural: bug spray, chapstick, toothpaste, etc. During the day while hiking, I would let out a loud holler of “hey oh” or “hey bear” so as to let my presence be known while walking through the park. And with these efforts, you could say that it had been working, as I had yet to see a bear.

A small campfire in a forest clearing at the edge of a meadow
A food bag hanging from a pole between trees
07.19.26 · 7:41 PMThe nightly routine: a fire to dry out shoes, and food hung out of reach.

But this last day, with only six miles left to my van, I was enjoying the sunshine with Yellowstone Lake to my left and huge sweeping views of its water making it look like an inland sea. To my right was a sea of sage, a bush about waist to chest in height with a turquoise color. I had just popped out of a thick patch of lodgepole pine and had my head down watching my step. It had been a little longer than usual since my last holler to make noise for bears when I looked up to see nothing but her snout up in the air. I froze in my tracks.

All I saw was her head, as she was in the sea of sage up to my right, only about 40 yards from me. Her head swayed back and forth, scanning like a metal detector on a beach looking for that lost treasure, but instead, her snout was up, smelling the landscape as she knew something was near. Bears have horrible eyesight, but their smell is out of this world. If we could train bears to sniff for drugs at an airport, we would.

But her head was unmistakable; it was a grizzly bear. She was dark brown with her snout in the air, close enough for me to see the saliva coming from her mouth, interrupting her morning breakfast of grasses and greenery. I began taking wider steps away from her, off trail and towards the lake to give her space, and at the same time, softly but firmly began talking to her, saying “hey bear,” so she knew I was there and to not startle her. Her gaze and nose detection went from swaying back and forth trying to find me, to instant radar lock like she was ready to launch a torpedo with extreme accuracy. In that moment, she stood from all fours to her hind legs and showed me her size. She was enormous.

Bears have poor eyesight, and therefore this action is mistaken by many as a predatory response. It’s not; she was simply getting a better look at me. When I first saw her, the sage cloaked her body and I only saw her head. Now standing up, she was immense. But little did I know, she wasn’t alone. Shortly after she stood, like dominoes, three cubs stood up in a row, one by one, also now exposing themselves while the sage covered everything except their heads. They were what we call COTY, or cubs of the year. Cubs will stay with their mother up to three years; these were born months ago. It was a surreal moment.

I kept backing away slowly and kept talking to her while she ushered her cubs away from me towards a distant treeline, and every five seconds, she would turn towards me and stand up to make sure I was walking away from her. It was a moment that lasted only 20 seconds, but felt like hours given that it was my first bear encounter in over 130 miles of backpacking the most remote region in the Lower 48.

A young grizzly bear standing in green grass
Grizzly bearPhotographed by Sean from a safe distance earlier this year. The encounter above went unphotographed, as it should.

I made it safely back to my van shortly after that and was buzzing from my first bear encounter. A part of me hoped I wouldn’t see one, but another giggled at the fact that the improbability of that was high. On paper, that was without a doubt the most dangerous thing I could expect to encounter on this trip. It was the star of the summer section, as the rest of the trip was grim with regards to weather. Many of the streams I wanted to fish were chocolate milk brown because of rain, and that hindered my fishing capabilities. But I was able to find water and land a 20-inch native Yellowstone cutthroat trout without another fisherman in sight.

A fly rod and reel resting on a gravel bar beside a stream
A native Yellowstone cutthroat trout held at the water's edge
A Yellowstone cutthroat trout beside a fly rod on the gravel
07.25.26 · 1:19 PMTwenty inches of native Yellowstone cutthroat, and no one else in sight.

Another highlight: I was able to hike to the Thorofare, a massive valley cut off from the world by over 32 miles of trail in any direction from a road. I went up and over the Continental Divide and skirted the caldera of the famous Yellowstone supervolcano. I got to see a place called “the Parting of the Waters,” the only place along the Continental Divide where water can flow up and over it, marking a unique and troubling conservation story where an invasive species had entered Yellowstone. I got near the headwaters of the Yellowstone River, the river of the park’s namesake and the longest undammed river in North America. The lifeblood of this park for its fish, its birds, its bears.

Sean, tiny in the frame, crossing a vast grassy valley ringed by mountains
07.22.26 · 8:00 AMDeep in the southeast corner, more than 30 miles from the nearest road.
Sean beside a trail sign reading Parting of the Waters, Atlantic Ocean 3488, Pacific Ocean 1353
A rocky butte rising above a meadow and burned timber
07.20.26 · 1:32 PMThe Parting of the Waters. Atlantic Ocean 3,488 miles one way, Pacific 1,353 the other.

And finally, I went out and found the solitude I had been looking for. I got to hike trails that I had dreamed of for over a decade and see mountains and rivers that I only fantasized about until now. I only saw about 12 people total in over 100 miles of trail. It was epic, but also spooky having bears walk yards from my tent while I slept, their presence made known the following morning on the trail with their scat and prints. It was a section that will be hard to beat, but fall beckons, and the bison and elk rut has begun, making herds of animals that take over the landscape, demanding respect. That section begins September 12th.

A cascading creek through a wildflower meadow below a peak
A high plateau of yellow wildflowers with layered mountains beyond
A tent pitched at the edge of a forest meadow
07.17.26 – 07.22.26About 12 people in over 100 miles.
A red-lit mountain reflected in a calm lake at sunrise, with fog on the water
07.19.26 · 5:41 AMFirst light.

Summer Stats

Days
9
Miles
147.42
Steps
343,910
Time hiked
58 h 40 m
Calories burned
21,000
People seen
~12
Highlights
Grizzly sow and three cubs, 20-inch Yellowstone cutthroat, the Thorofare, the Parting of the Waters

In the pack: Airtex Long Sleeve Hooded Shirt · Cordura® Utility Short · Cordura® Expedition Pant · Cordura® Packable Windbreaker

Field Note 01 · Leg complete

Spring

On trailJune 9–12, 2026
SectionSouthwest corner
RouteOld Faithful to Shoshone Lake

Words and photos by Sean Jansen

It was almost a dream. Opening a map of Yellowstone National Park for the first time and seeing the vastness of the terrain it had to offer. My map had some shaded relief, so I was able to see the drama of the mountain ranges, the hydrology of the rivers, and the extent of its valleys. My eyes wandered and followed the roads to different destinations and features with names ranging from the Grand Prismatic to the Lamar Valley, curious what their origins were. Following further, my eyes found even smaller lines than the roads. These lines were dotted and slithered out and away from the roads like the hair from someone’s head, each going in directions of their choosing. They were trails.

I’d follow them around the map while they nearly circumnavigated the park. A park with 2.2 million total acres that could engulf the entire state of Rhode Island with plenty of room to spare. The trails went three quarters of the way around before eventually stopping at a road, failing to continue further. I felt deflated, stopped the daydream, and closed the map. I always wanted to backpack a loop around the entire park, but when my eyes discovered the trails stopped nearly all the way round, the dream somewhat died and I went off to pursue other backpacking and outdoor interests around the world. The Pacific Crest Trail on the west coast, a paddle trip down the Baja Peninsula of Mexico, and my latest venture and blog post for Florence Marine: Tideline to Alpine, backpacking Southern California for southern steelhead trout.

Working in Yellowstone as a guide to fund these trips, the dream of circumnavigating the park was tumbling around the back of my mind, but I couldn’t figure out how to do it without road walking. I wanted to see the park’s backcountry. I wanted to get away from the tourists and see what the wilderness had to offer. And I wanted to come eye to eye with its animals: the grizzly bear, the wolf, and the bison as the most noteworthy.

A quiet river bend lined with conifers under a blue sky
06.09.26 · 6:14 PMThe backcountry most visitors never see.

I was chained largely throughout my life by the summer months in the park. Growing up in San Clemente, Yellowstone was a far cry from what would interest any blond-haired, blue-eyed surfer kid, but between summer breaks at school, as a family, that’s where we went. I learned to fly fish at the age of eleven and fell in love with wildlife photography thanks to my mom. After college, I eventually moved to Yellowstone and got a job as a guide. But once again, always tethered to the summer months.

It wasn’t until recently that my winters of chasing swells on the west coast started to change and instead, I began chasing powder and wolves. The wolves are more active throughout the day and somewhat easier to spot, so I spent my last three winters in Yellowstone exploring. I fell in love with splitboarding and learned how to cross-country ski. And after a day in the park, skiing into a remote wilderness region and stumbling upon three moose within touching distance of the snow-covered trail, I came up with my circumnavigation of the park, but doing so over four seasons.

Summer was all I knew in Yellowstone, for over 27 years of visiting. But when I re-looked at my backcountry map of the park and saw that the trails stopped at a road in the northwest corner, I figured I could cross-country ski in winter down to the next trails on those roads that aren’t snowplowed to reconnect the loop. With that in mind, I set out to plan the entire loop over four seasons, with the final leg being on groomed cross-country ski trails or roads in winter. It would check the box of seeing more than summer in the park, check the box of fully circumnavigating the park in its backcountry, and it would finally close a chapter and a dream that’s been tumbling in my mind for over 13 years.

Spring on the calendar hits on March 20th. But that hardly meant that Yellowstone got the memo. When I first moved to the area, I learned very quickly that Yellowstone really only had two seasons: winter and July. Snow can hit any month of the year, and I have personally seen it snow on the high mountain peaks on Independence Day. So, when planning the trip, I wanted to see the park when the spring snowmelt was in full swing and the grasses and flowers were blooming. And with the timing of the backcountry office in the park being open for business, the second week of June seemed the appropriate time.

I gathered my permit, shouldered my pack, and took off down the trail with the infamous geyser of Old Faithful in my rearview. I chose the southwest corner of the park for spring because of the lack of major river crossings. It also coincided with walking the shores of a massive lake, the largest backcountry lake in North America, and that is Shoshone Lake. I have previously stand-up paddled this backcountry lake twice and felt it was a great, comforting start to the trip. But little did I know that this section was to set the tone for the rest of the seasons, as on the first night of my trip, I was greeted by two things: ample sign of bear, and snow.

Sean with a loaded backpack standing beside an erupting geyser
06.09.26 · 12:09 PMDay one. A major geyser erupts along the route to camp.

I was well equipped and did just fine throughout the night, but that didn’t change the fact that I had to dig into my experience to deal with the temperature and moisture, not to mention my first night of the trip sleeping in grizzly bear territory, alone. But I wouldn’t have had it any other way. I passed a major geyser en route to camp and witnessed hot springs that steamed and vented from the earth.

Sean standing over a smoking campfire in a pine forest
A tent pitched among fallen lodgepole pines
06.09.26 · 3:39 PMFirst camp. The only campfire of the spring leg, and a first night alone in grizzly country.

As I backpacked deeper into the park, the more remote it felt and the less human activity I came across. The trail was covered in last night’s dusting of snow and my feet crunched atop the frozen ground. The skies were sunny, but with each mile I gained, so too did the cloud cover.

Sean hiking a snow-covered trail through lodgepole pine forest
06.10.26 · 1:31 PMLast night’s snow, still on the trail.

I would roller coaster up and down passes and hills covered in lodgepole pine forest, the most dominant tree in the park, and hardly noticed or heard any wildlife thanks to the muffled density of the forest. Arriving on the shores of Shoshone Lake was a reprieve, but that coincided with Mother Nature not agreeing to the comfort of its shores. Upon my arrival, bang! A crack shot through the sky.

Lightning pierced the grey canopy of the trees and a flash of purple and pink shot through the landscape like someone flicked the lights of a bedroom on and off. Immediately after what sounded like a gunshot echoing throughout the forest, I felt the first flake fall from the sky. Thundersnow was upon me.

I quickly unshouldered my pack and placed it fifty yards away from me while I sat crouched, huddled under a pine tree. More lightning and thunder shook the earth and denser snow began to fall. My pack was adorned with a graphite fly rod to feed my interest in fly fishing on the trip. I had a carbon fiber tripod for photography, and my hiking poles were made of aluminum. I was asking to be thunderstruck, as AC/DC would put it.

The thunder passed and I stumbled my way down the trail, but what remained was heavy snow. It blanketed the landscape, and as I arrived at camp, I needed to quickly set up my tent before hypothermia set in. With planning ahead, my backpack was lined with a trash bag to keep everything dry: my sleeping bag, Off Grid Fleece Half Zip, and Pertex Down Puffer for starters.

Snow-covered forest along the shore of Shoshone Lake under a dark sky
Close view of snow-laden conifers
06.10.26 · 5:14 PMShoshone Lake after the thundersnow.

As quickly as it hit, it was over, but not without blanketing the landscape with 2 to 4 inches of fresh powder. It was June tenth. Morning beckoned with sheer blue skies and sun, and with that came the near rain-like moisture dripping down from the treetops as the snow melted throughout the day. My 2.5 Layer Shell and Cordura Expedition Pant were lifesavers as they kept me dry and insulated while hiking through the snow, rubbing up against wet bushes.

Tent and gear in a forest camp covered in fresh snow
A camp stove and coffee on the snowy ground
06.11.26 · 9:11 AMFresh powder in June. Coffee first.

Other than the snow, the spring section of the trip remained uneventful as far as wildlife. I witnessed lake trout swimming along the bottom of the crystal-clear waters while I enjoyed my coffee. Trumpeter swans cruised the shore in unison, their white feathers matching the snow across the landscape, and sandhill cranes gawked into the landscape. But no other wildlife was spotted. Bears were present based on their scat and some tracks along the trails, but nothing recent or noteworthy to make me more on guard than normal.

A lake trout visible over rocks in clear, shallow water
A trumpeter swan swimming near shore
06.11.26 · 7:50 AMLake trout below, trumpeter swans alongside.
Sean standing on the shore of Shoshone Lake under blue skies
06.11.26 · 11:14 AMShoshone Lake. Two nights on its shores.

The southwest corner of the park was covered, and the spring section was wrapped up. It was everything I wanted it to be and was also nothing I expected it to be. I saw thermal features, I saw weather, and I saw the largest backcountry lake in North America, camping two nights on its shores. I attempted to cast out to its fish but remained unlucky in the endeavor. Summer is up next and that will be over 100 miles of backpacking into the most remote region in the Lower 48. What I lacked in the spring section for wildlife, I’m sure I will make up for in the summer section. That will begin July 17th.

Silhouette of Sean fly casting from the lakeshore with snowy peaks behind
06.11.26 · 7:44 PMCasting into Shoshone Lake. No luck, this time.
Alpenglow on a snow-streaked mountain
Tent pitched above the lake at dusk
Sean resting on a hillside above a winding river
06.11.26 – 06.12.26Last light, last camp, last morning of the spring leg.

Spring Stats

Days
4
Miles
35.22
Steps
100,448
Time hiked
14 h 11 m
Calories burned
5,068
Campfires
1
Animals
Sandhill crane, trumpeter swan, beaver, lake trout, white-tailed deer

In the pack: 2.5 Layer Shell · Cordura Expedition Pant · Off Grid Fleece Half Zip · Pertex Down Puffer

Four seasons, one circle, and a park most people only see through a windshield. We’ll keep adding to this page as Sean closes the loop. 🚩

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