Androscoggin County is a county in the U.S. state of Maine. As of the 2020 census, the county's population was 111,139. Its county seat is Auburn and its most populous city is Lewiston. Androscoggin County comprises the Lewiston-Auburn, Maine metropolitan statistical area and is partially included in the Lewiston-Auburn, Maine, Metropolitan New England City and Town Area. It is also a part of the Portland-Lewiston-South Portland, Maine combined statistical area.