what county is marienville pa?
Homefacts City Report. Marienville is located in Forest County, PA. The population is 1,977, making Marienville the largest city in Forest County. There are 2 public schools in Marienville with an average Homefacts rating of C+. The total crime rate for Marienville is very low, and there are 2 registered sex offenders residing in the city.