Yellowstone National Park

Yellowstone National Park

Isa Lake

Hiram Chittenden of the U.S. Army Corps of Engineers claimed to have discovered this lake on the Continental Divide at Craig Pass in 1891. Chittenden, who built many early roads in Yellowstone, was searching for a practicable route to locate his new road between Old Faithful and West Thumb. It was not until 1893 that Northern Pacific Railroad (NPRR) officials named the lake for Isabel Jelke of Cincinnati. Little is known about Jelke or about her relationship to Chittenden, the NPRR, and Yellowstone. Chittenden's 1916 poetic tribute to the lake and his discovery includes the puzzling line: "Thou hast no name; pray, wilt thou deign to bear/The name of her who first has sung of thee" (Verse, p. 53). Perhaps Isabel Jelke was already associated with the lake when Chittenden "discovered" it.

Isa Lake is noteworthy as probably the only lake on earth that drains naturally to two oceans backwards, the east side draining to the Pacific and the west side to the Atlantic.


I have always wondered, how is Isa pronounced when referencing the lake?  I read somewhere it is pronounced "I'sa" but have never had the opportunity to hear anyone "official" say it.

Hi Tracie,

I just spoke with someone who has worked in Yellowstone National Park for many years and she pronounces Isa lake as "Iza Lake" with a "Z". I am not completely certain if this is the correct way, but she is a reliable source. Hope that helps!