 The Emmett area was transferred to Canyon County at its establishment in 1892.At the 1910 Census, three Emmett area precincts contained a population of 2,601 while three Boise County precincts of Upper Squaw Creek, Lower Squaw Creek, and Pearl contained 1,069 residents.The Black Canyon Diversion Dam on the river was built in the early 1920s, east of Emmett.