Ada County, Idaho

Ada County is in southwest Idaho. This is home to Boise, the state capitol and largest city in Idaho. Ada County was named in honor of Ada Riggs, the daughter of H. C. Riggs, a cofounder of Boise. She was the first pioneer child born in the area. Ada County contains 1,055 square miles of land and 5 square miles of water. Ada County was created by the Idaho Territorial Legislature in 1864. Ada County was larger in those days, until Canyon County was partitioned from Ada County in the early 1890's. The county seat is Boise.