Fitchburg is a city in northern Worcester County, Massachusetts, United States. The third-largest city in the county, its population was 41,946 at the 2020 census. Fitchburg is house to Fitchburg State University as with ease as 17 public and private elementary and high schools.

Fitchburg was first granted in by Europeans in 1730 as portion of Lunenburg, and was officially set apart from that town and incorporated in 1764. The area was back occupied by the Nipmuc tribe. It is named for John Fitch, one of the committee that procured the battle of incorporation. In July 1748 Fitch and his family, living in this without help spot, were abducted to Canada by Native Americans, but returned the adjacent 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 top of its mill town prosperity. A few examples of these 19th century buildings are the Fay Club, the outdated North Worcester County Courthouse and the Bullock house.

As the city is one of Worcester County’s two shire towns, it has hosted the Northern Worcester County Registry of Deeds, established in 1903, and the county jail on Water Street.