Waltham is a city in Middlesex County, Massachusetts, United States, and was an early center for the labor movement as well as a major contributor to the American Industrial Revolution. The original home of the Boston Manufacturing Company, the city was a prototype for 19th century industrial city planning, spawning what became known as the Waltham-Lowell system of labor and production. The city is now a center for research and higher education as home to Brandeis University and Bentley University. The population was 65,218 at the 2020 United States census. Waltham is part of the Greater Boston area and lies 9 miles (14 km) west of Downtown Boston.