In the deep wilderness of Bridger-Teton National Forest, not far from the southern border of Yellowstone National Park, hikers can find a small stream with two forks, each flowing downhill in different directions.
A sign is posted on one of the trees standing on an island between the two forks of the creek. A simple inscription attests to the remarkable natural wonder of the waters.
“Continental Divide – Elev. 8200 – Two Ocean Pass – Parting of the Waters – Two Ocean Creek.”
“One branch heads to the Atlantic Ocean and the Gulf of Mexico, and one branch goes to the Pacific Ocean,” said Mark Fisher, Wyoming geologist and contributor to the website Geology of Wyoming. “It’s a unique feature on the Continental Divide.”
Two Oceans, One Creek
Two Ocean Creek, located high in the mountains along Two Ocean Pass, is one of Wyoming’s lesser-known geological wonders. The 3-mile-long creek is positioned so that its water will eventually flow into either the Atlantic or Pacific oceans.
H.H. “Rip” Van Winkle, the Teton National Forest Supervisor from 1957-1963, described it as “the Y” and surmised that its water had flowed toward both oceans for hundreds of years.
“In lowest water stages, the creek is four or five feet wide and about six inches deep,” he wrote. “It divides into approximately equal streams. Atlantic and Pacific Creeks. The division takes place in the timber, rather than in the open park ... (and) fish can cross the Continental Divide in the two creeks.”
Two Ocean Pass was listed as a National Natural Landmark Site in 1965, but that hasn’t increased its visibility to the wider world. That doesn’t detract from its importance to the Greater Yellowstone Region and its status as one of the most significant waterways in North America.
Sea To Shining Sea
At the Parting of the Waters, it’s 3,488 miles to the Atlantic Ocean and 1,353 miles to the Pacific Ocean. Whichever way the water flows, it’s got quite a trek ahead.
Eastward water in Atlantic Creek flows into the Yellowstone River, continuing into the Missouri River, then the Mississippi River, and finally to the Gulf of Mexico. Westward water in Pacific Creek flows into the Snake River and then to the Columbia River, which empties into the Pacific Ocean.
Two Ocean Pass will often flood during a wet spring. This creates a temporary expanse of marshland where water can more easily reach Two Ocean Creek at “the Y.”
That flooding makes Two Ocean Creek an important migratory route for Yellowstone’s native cutthroat trout. The fish use the high-elevation waterway to migrate between the Snake and Yellowstone rivers.
However, the creek is also a corridor for invasive species. A 2020 study by the National Park Service and U.S. Geological Survey revealed that nonnative lake trout may have used Two Ocean Creek to reach the Greater Yellowstone Ecosystem, and if other fish species do the same in the future, it could become an ecological liability.
“We conclude that invasive movements by lake trout from the Snake River over Two Ocean Pass may have resulted in their colonization of Yellowstone Lake,” the paper reads. “Moreover, Yellowstone Lake may be vulnerable to additional invasions because several other nonnative fish inhabit the upper Snake River.”
But how did such a unique waterway come to be? The answer lies in Wyoming’s volcanic history, long before the nearby supervolcano forced its way into the neighborhood.
Parting of the Waters is a spot in Wyoming where water from North Two Ocean Creek can flow to either the Pacific Ocean to the west or Atlantic to the east. This wooden sign indicates it’s 3,488 miles to the Atlantic and 1,353 miles to the Pacific. (Cowboy State Daily Staff) 
A 1894 drawing outlines Two Ocean Creek as it flows into Two Ocean Pass. Top center, Atlantic Creek flows out, while Pacific Creek flows southwest near the bottom of the drawing. (Cowboy State Daily Staff) 
Two Ocean Lake in the Teton Wildnerness of Wyoming. (J. Bonney, National Park Service)
From Gardiner To Dubois
The Continental Divide lies along the entire 3,000-mile expanse of the Rocky Mountains. A visitor driving through Yellowstone could cross the divide three times during their visit.
Adjacent to the relatively young Yellowstone volcano, there’s the much older volcanic rock of the Absaroka Volcanic Province. The expanse of 50-million-year-old rock stretches 160 miles long and nearly 50 miles across.
Wyoming is known for being incredibly diverse geologically, sitting on some of the oldest, most stable bedrock in North America. Fisher said the Absaroka Volcanic Province exemplifies the Cowboy State's pre-Yellowstone volcanism.
“This is not Yellowstone,” he said. “The Yellowstone stuff is within the last two million years. The Absaroka Volcanic Province runs from North Yellowstone in Montana, from Gardiner and Cooke City, south of Cody, and almost To Dubois.”
Two Ocean Pass is contained entirely within the Absaroka Volcanic Province, a vast volcanic field created by the uplift of the Rocky Mountains over 50 million years ago. The rugged terrain created from that uplift created the quirk of geology that allows Two Ocean Creek to split and flow downhill to the Atlantic and Pacific Oceans.
While it is located within the Greater Yellowstone Region, Fisher said, Yellowstone itself had nothing to do with creating Two Ocean Creek, even if it directly benefits from it.
“Those rocks erupted so long ago that it was cold, extinct volcanic field by the time Yellowstone did its thing,” he said. “That’s what created this rare geologic feature.”
Lewis And Clark Missed Out
There is a “path” to Two Ocean Pass, but a round-trip hike requires a 40-mile trek along the Atlantic-Pacific Trail and an extra quarter-mile to reach the Parting of the Waters. None but the most intrepid hikers and riders will get to say they’ve seen the stream that feeds two oceans.
Meriwether Lewis and William Clark were two people who would have wanted to make the trek to the Parting of the Waters. In 1803, they were tasked with finding a waterway connecting the two oceans on either side of the burgeoning United States.
“The object of your mission is to explore the Missouri River,” President Thomas Jefferson wrote to Lewis in 1803, “and such principal streams of it, as, by its course and communication with the waters of the Pacific Ocean, whether the Columbia, Oregon, Colorado, or any other river, may offer the most direct and practicable water-communication across the continent, for the purposes of commerce.”
Lewis and Clark followed the Mississippi River upriver into North Dakota and Montana, where they reached the headwaters of the Missouri River. They eventually went overland to the Columbia River and reached the Pacific Ocean in November 1805, but never found a communicable waterway connecting east to west.
Two Ocean Creek isn’t the commercial water route Jefferson hoped Lewis and Clark would discover. Nevertheless, it’s precisely what he wanted to find – an uninterrupted passage across the continent.
Two decades later, Jim Bridger discovered what had eluded Lewis and Clark deep in the Wyoming wilderness. It’s only fitting that Two Ocean Pass and Two Ocean Creek reside in the national forest that bears Bridger’s name.
Given the effort it takes to get there, Fisher’s never been to Two Ocean Pass to see the Parting of the Waters. But he doesn’t need to see it to recognize its provenance for Wyoming and North America.
“The landscape is positioned in such a way that the creek just so happens to divide to reach both oceans,” he said. “I wouldn’t say I’m an expert on the Continental Divide, but I don’t know of anywhere else like Two Ocean Creek.”
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
