Mammoth Spring is a city in Fulton County, Arkansas. The population was 929 at the time of the 2020 census and is home to Mammoth Spring, one of the largest natural springs in the world. The location is renowned for its trout fishing.

Fulton County is a county located in the U.S. state of Arkansas. As of the 2020 census, the population was 12,075. The county seat is Salem. Fulton County was formed on December 21, 1842, and named for William Fulton, the last governor of the Arkansas Territory. It is an alcohol prohibition or dry county.