Fitchburg is the third largest city in Worcester County, Massachusetts, United States. The population was 40,318 at the 2010 census.
Fitchburg was first settled in 1730 as part of Lunenburg, and was officially set apart from that township and incorporated in 1764. It is named for John Fitch, one of the committee that procured the act of incorporation.In July 1748 Fitch and his family, living in this isolated spot, were abducted to Canada by Native Americans, but returned the next year.Fitchburg is situated on both the Nashua River and a railroad line. The original Fitchburg Railroad ran through the Hoosac Tunnel, linking Boston and Albany, New York. The tunnel was built using the Burleigh Rock Drill, designed and built in Fitchburg. Fitchburg was a 19th-century industrial center. Originally operated by water power, large mills produced machines, tools, clothing, paper, and firearms. The city is noted for its architecture, particularly in the Victorian style, built at the height of its mill town prosperity. A few examples of these 19th century buildings are the Fay Club, the old North Worcester County Courthouse and the Bullock house.As the city is one of two shire towns, the Northern Worcester County Registry of Deeds, established in 1903, and the county jail on Water Street were two county facilities located in Fitchburg.The 1961 film Return to Peyton Place was filmed in Fitchburg.