Salmon is a city in Lemhi County, Idaho, United States. The population was 3,112 at the 2010 census. The city is the county seat of Lemhi County.Located in the Lemhi River valley, Salmon is home to the Sacajawea Interpretive Culture and Education Center, which focuses on Lemhi Shoshone culture, as well as the interaction between Sacagawea and other Shoshone and Lewis and Clark.