Ohio County.
Petroleum County
County Leitrim is the least populated at around 28,500 people.
According to census.gov, Taliaferro County, Georgia, has the least population at 1,884 people in 2007.
Issaquena County is the least populated county in Mississippi with a population of 1,406 as of the U.S. 2010 Census.
Menominee county, at just over 4,200 residents.
Wirt County, with a 2008 population of 5,757.
Northumberland is the least densely populated county in England, with a population density of around 62 people per square kilometer.
Liberty County recorded 7,021 people in the US Census of 2000 which marks it as both the least populated and least densely populated county in Florida. It was a close race with Lafayette County which recorded 7,022 residents.
Northumberland is the least populated county so it may be a candiate.
The least populated county in Florida is Liberty County, with a population of approximately 8,300 people.
Menomonie it only has about 4,500 people.