Resident Population in Penobscot County, ME was 155.31200 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Penobscot County, ME reached a record high of 155.31200 in January of 2023 and a record low of 125.39300 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Penobscot County, ME - last updated from the United States Federal Reserve on May of 2024.