The Idaho Legislature created Canyon County from Ada County in an act approved March 7, 1891, effective at the November 26, 1892, election. Caldwell was established as the county seat. The county originally contained all of Canyon and Payette counties and part of Gem; Gem County formed in 1915 and Payette County in 1917. Some sources attribute the name to the canyon of the Boise River near Caldwell, while western writers John Rees and Vardis Fisher believed it was named for the Snake River canyon, which forms a natural boundary with Owyhee County to the south and west.
The Idaho Legislature created Canyon County from Ada County in an act approved March 7, 1891, effective at the November 26, 1892, election. Caldwell was estab.lished as the county seat. The county originally contained all of Canyon and Pa,yette counties and part of Gem; Gem County formed in 1915 and Payette County in 1917. Some sources attribute the nam,e to the canyon of the Boise River near Caldwell, while western writers John Rees and Vardis Fisher believed it was named for the Snake River canyon, which forms a natural boundary with Owyhee County to the south and west.