Manassas City, VA - Resident Population in Manassas city, VA was 42.69600 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Manassas City, VA - Resident Population in Manassas city, VA reached a record high of 42.76500 in January of 2021 and a record low of 11.01800 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Manassas City, VA - Resident Population in Manassas city, VA - last updated from the United States Federal Reserve on May of 2024.