Nampa ( (listen)) is the largest city of Canyon County, Idaho. Its population was 81,557 at the 2010 census and grew to 100,200, according to the 2020 Census. It is Idaho's third-most populous city. Nampa is about 20 miles (32 km) west of Boise along Interstate 84, and six miles (10 km) west of Meridian. It is the second principal city of the Boise-Nampa metropolitan area. The name "Nampa" may have come from a Shoshoni word meaning either moccasin or footprint.