Mainville is a census-designated place in Columbia County, Pennsylvania, United States.

Pennsylvania Route 339 serves Mainville, leading 5 miles (8 km) northeast to Mifflinville and Interstate 80, and south 21 miles (34 km) up the Catawissa Creek valley and over Locust Mountain to Mahanoy City.

Bloomsburg, the Columbia County seat, is 5 miles (8 km) to the northwest via Mainville Road.

29.7% of all households were made up of individuals, and 13.5% had someone living alone who was 65 years of age or older.

There were no families and 7.7% of the population living below the poverty line, including no under eighteens and none of those over 64.