http://www.cityofboise.org Boise ( /ˈbɔɪsiː/) is the capital and most populous city of the U.S. state of Idaho, as well as the county seat of Ada County. Located on the Boise River, it anchors the Boise City-Nampa metropolitan area and is the largest city between Salt Lake City, Utah and Portland, Oregon. As of the 2010 Census, Boise's city population was 205,671. The Boise metropolitan area is home to about 616,500 people and is the most populous metropolitan area in Idaho, and the third most populous metropolitan area in the U.S. Pacific Northwest region (behind only the Seattle, WA and Portland, OR metropolitan areas). It is also the 104th largest U.S. city by population.