Lamar River Drainage Professional Review and Guide
"The Lamar River rises on the west flank of the Absaroka Range, which defines Yellowstone National Park’s eastern border. 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. The river is more than 43 miles long, making it the largest single tributary basin to the Yellowstone River within the park.
From the angler’s perspective, the defining characteristic of the Lamar is its tendency to get quite muddy from the lightest of rains. This eTrail contains information on Lamar River (Hoodoo Basin to Soda Butte Creek, Soda Butte Creek to the Yellowstone Confluence), Soda Butte Creek (Headwaters to Pebble Creek, Pebble Creek to Lamar River), Cache Creek, Pebble Creek, and Trout Lake."