Gem County, Idaho County, Idaho were: Gem County, Idaho Gem County is a county in the U.S. state of Idaho. As of the 2010 census, the population was 16,719. The county seat and largest city is Emmett. Gem County is part of the Boise, ID Metropolitan Statistical Area. Gem County is home to the Idaho ground squirrel. Named for the state nickname, "Gem State," the county was established on March 15, 1915, partitioned from Canyon County and Boise County. Fur trappers were in the area as early as 1818, and Alexander Ross explored Squaw Creek in 1824. Prospectors and miners moved through the
California State Route 223 highway. It was a part of Legislative Route 140, which ran from Taft to US 99 (locally known as Taft Highway), and from US 99 to US 466. The Taft Highway portion was signed as US 399, but the Bear Mountain Boulevard section was unsigned. It was dropped from the route in 1959, and became Legislative Route 264. In 1964, with the renumbering of California’s state routes, Bear Mountain Boulevard became a signed route as SR 223, and was extended west to I-5. California State Route 223 State Route 223 (SR 223) is a state route in Kern County, California,