Tomah is a city in Monroe County, Wisconsin, United States. The population was 9,570 as of the 2020 census. The city is surrounded …Tomah is a city in Monroe County, Wisconsin, United States. The population was 9,570 as of the 2020 census. The city is surrounded by the Town of Tomah and the Town of La Grange. Tomah was founded by Robert E. Gillett in 1855 and incorporated as a city in 1883, but the charter was not issued until 1894. It is named after Thomas Carron, a trader at Green Bay who had integrated into the Menominee tribe. The Menominees pronounced the name Tomah or Tomau and he became known as Chief Tomah. Tomah was adopted as the name for the settlement in Monroe County on the unsubstantiated belief that Chief Tomah had once held a tribal gathering in the area.