Foss is a town in Washita County, Oklahoma, United States. As of the 2010 census, the town population was 151, an 18.9 percent increase from 127 at the 2000 census.
The history of Foss began when settlers from the area of the Wilson post office moved four miles north to the valley of Turkey Creek in the late 1890s. They initially wanted their new post office to be called Graham, but since that name was already taken it was named Maharg (an anagram of Graham). A flash flood on May 2, 1902 wiped out the town on Turkey Creek, destroying businesses and drowning several people. The town rebuilt on higher ground and was named Foss. The post office began operation on September 15, 1900.
The town expanded rapidly. By 1905 the town had a population between 900 and 1000 residents. It had two banks, three cotton gins, and by 1912 had an electric plant, two hotels and an opera house.