Middleton is a city in Canyon County, Idaho, United States. The population was 2,978 at the 2000 census. It is part of the Boise City–Nampa, Idaho Metropolitan Statistical Area.
Middleton, one of the oldest settlements in the state, was named because it was midway between Boise and an old ferry on the Snake River. It had a stage station in the early days of the Oregon Trail, a post office in 1866 and a water powered gist mill in 1871. The Ward Massacre occurred near the site in 1854.
Middleton is the oldest settlement in Canyon County, with the land being parceled out in 1863 by William N. Montgomery. The Boise River flooded in 1872 and cut a new channel, isolating the town on an island; as a result, the town moved to a new location in the years after 1880. The town incorporated as a city in 1910 (although the certificate wasn't issued until 1971.) The present mayor is (as of 2009): Vicki Thurber. On February 1, 2007, 78% of Middleton High School burned down, caused by the overheating of a fan above the weight room. The 42-year old building was not equipped with sprinklers to prevent the fire.