The Lamar River is the largest tributary of Yellowstone River within Yellowstone National Park. We are fortunate not to have to use the full moniker, Lucius Quintus Cincinnatus Lamar, of the Secretary of the Interior for whom the river is named. It originates in the high peaks, steep ridges, U-shaped valleys of the Absaroka-Beartooth Mountains and it is approximately 40 miles long. Large herds of Bison and Elk lazily graze along the river in the Lamar Valley. Wolves can even occasionally be spotted if you are an early riser or get lucky in the evening and it is one of the best places in Yellowstone to spot Grizzlies.
The Upper Lamar River is another tremendous cutthroat fishery. The main river along with tributaries such as Cache, Miller and Cold creeks fish very well with dry flies for 12"-18" cutthroats. As with all of backcountry trips the wildlife, wildflowers and scenery are tremendous. wolves, grizzly bears, elk, bison, deer and moose are among some of the wildlife you may encounter in this area of the park.
The Lamar River receives a lot of fishing pressure, due to both its spectacular scenery and quality fishing and because the river is easily accessible by road. Generally, the Lamar ranges from between 25-200 yards away from the road, allowing for easy access, and hiking down to the river is easy.
Prior to the 1884-85 Geological Survey of the park, the Lamar was known as the East Fork of the Yellowstone River. During that survey, Geologist Arnold Hague named the river for L.Q.C. (Lucius Quinctius Cincinnatus) Lamar, then Secretary of the Interior.
In 1869, the Cook-Folsom-Peterson Expedition encountered the Lamar River (East Fork) just upstream from the canyon section flowing into the Yellowstone and traveled upstream to the confluence of Calfee Creek where they camped on September 16, 1869.
Osborne Russell in his 1921 Journal of a Trapper described the Lamar as follows: Chapter-VI-In the Yellowstone Country-A Garden of Eden Inhabited By a Small Party of Snake Indians - On the 28th [July 1834] we crossed the mountain in a westerly direction through the thick pines and fallen timber, about twelve miles, and encamped in a small prairie about a mile in circumference. Through this valley ran a small stream in a northerly direction, which all agreed in believing to be a branch of the Yellowstone. 29th-We descended the stream about fifteen miles through the dense forest and at length came to a beautiful valley about eight miles long and three or four wide, surrounded by dark and lofty mountains. The stream, after running through the center in a northwesterly direction, rushed down a tremendous canyon of basaltic rock apparently just wide enough to admit its waters. The banks of the stream in the valley were low and skirted in many places with beautiful cottonwood groves. Here we found a few Snake Indians comprising six men, seven women and eight or ten children, who were the only inhabitants of the lonely and secluded spot.