Resident Population in Cumberland County, ME was 313.80900 Thous. of Persons in January of 2024, according to the United States Federal Reserve. Historically, Resident Population in Cumberland County, ME reached a record high of 313.80900 in January of 2024 and a record low of 192.52800 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Cumberland County, ME - last updated from the United States Federal Reserve on April of 2026.