From Yellowstone Wiki
Isa Lake is a very small, oblong lake that straddles the section of Grand Loop Road between Old Faithful and West Thumb, 7.7 miles south of Old Faithful Junction, right on the Continental Divide at Craig Pass. The Isa Lake Bridge traverses the lake.
Isa Lake has the unique distinction of draining into both the Gulf of Mexico and the Pacific Ocean; backwards, in fact. The western portion drains via Spring Creek to the Firehole River, to the Madison River, then onto the Missouri and Mississippi Rivers into the Gulf of Mexico, while the eastern portion drains via Delacy Creek to the Shoshone Lake, then into the Lewis River, the Snake River, and finally into the Columbia River where it finds its way into the Pacific Ocean.
The lake was named by Northern Railroad officials in 1893 for Isabel Jelke, a young woman from Cincinnati, who was apparently one of the first people to traverse the new roadway Chittenden had built across the lake. Little is known about any specifics regarding her relationship to NPRR or any other person/feature associated with the park.
The lake itself is quite popular with tourists as it sits at the westernmost turnout for the Continental Divide, complete with an auto pullout and signage. The lake is often covered with yellow ponds lilies in the summer and ices over in the winter. The lake is fishless.
- Location: 44.44055841 -110.7198019
- Size: 1/2 acre
- Perimeter: 926 feet
- Depth: Unsurveyed, but very shallow
- Haines, Aubrey L. (1996). The Yellowstone Story : A History of Our First National Park : Volume I. 2nd Edition. ISBN: 0870813900
- Haines, Aubrey L. (1996). The Yellowstone Story : A History of Our First National Park : Volume II. 2nd Edition. ISBN: 0870811169
- Pierce, Steve. (1987). The Lakes of Yellowstone: A Guide for Hiking, Fishing, and Exploring. ISBN: 089886139X
- Varley, John D., and Paul Schullery. 1998. Yellowstone Fishes: Ecology, History, and Angling in the Park. ISBN: 0811727777
- Whittlesey, Lee H. (2006). Yellowstone Place Names. ISBN: 1599717166
- Geographic Names Information System, U.S. Geological Survey.
- Yellowstone National Park, Spatial Analysis Center, Geographic Information System database. Accessed in October, 2010.