Firth Map
Firth is a city in Bingham County, Idaho, United States. The population was 408 at the 2000 census.
Firth is located at 43°18?20?N 112°11?02?W / 43.305519°N 112.183938°W / 43.305519; -112.183938 (43.305519, -112.183938).
According to the United States Census Bureau, the city has a total area of 0.2 square miles (0.5 km2), all of it land.
Nearby cities include Blackfoot, Idaho Falls, Ammon, Iona, Shelley.