Judith Basin County, Montana: History
Judith Basin County was formed of area taken from western Fergus County and eastern Cascade County on December 10, 1920. The county derives its name from the Judith River. In 1895, Yogo sapphires were discovered at Yogo Gulch, about 15 miles southwest of Utica, which at the time was in Fergus County.
In 2022 the invasive Eastern Heath Snail was found in the county.