Ada County was created by the Idaho Territorial Legislature on December 22, 1864, partitioned from Boise County. It is named for Ada Riggs, the first pioneer child born in the area and the daughter of H.C. Riggs, a co-founder of Boise. Canyon County, which originally included Payette County and most of Gem County, was partitioned from western Ada County in 1891.
Register for the Ada County Property Portal