|Founded||March 7, 1891|
|• Total||604 sq mi (1,560 km2)|
|• Land||587 sq mi (1,520 km2)|
|• Water||16 sq mi (40 km2) 2.7%|
|• Density||394/sq mi (152/km2)|
|Time zone||UTC−7 (Mountain)|
|• Summer (DST)||UTC−6 (MDT)|
Canyon County is a county in the U.S. state of Idaho. As of the 2020 census, 231,105 people lived there, making it the second-most populous county in Idaho. The county seat is Caldwell, and largest city is Nampa.