Ammon is a city in Bonneville County, Idaho, United States. As of the 2000 census the population of Ammon was 6,187, with an estimated 2006 population of 12,065.
Having nearly doubled in size since 2000, Ammon is among the fastest-growing cities in Idaho. It is part of the Idaho Falls, Idaho Metropolitan Statistical Area.
Ammon was founded by members of The Church of Jesus Christ of Latter-day Saints in 1888. It was originally called South Iona because it was the dependent branch in the south end of the Iona, Idaho ward. The area was made a ward in the church in 1889 with Arthur M. Rawson as bishop, who renamed the town in honor of Ammon, a figure in the LDS book of scripture, the Book of Mormon. Since it was now independent of the Iona Ward, a new name seemed appropriate.