The American Antiquarian Society (AAS), located in Worcester, Massachusetts, is both a learned society and a national research library of pre-twentieth-century American history and culture. Founded in 1812, it is the oldest historical society in the United States with a national focus. Its main building, known as Antiquarian Hall, is a U.S. National Historic Landmark in recognition of this legacy. The mission of the AAS is to collect, preserve and make available for study all printed records of what is now known as the United States of America. This includes materials from the first European settlement through the year 1876.

Worcester is the 2nd most populous city in the U.S. state of Massachusetts and the 114th most populous city in the United States. Named after Worcester, England, the city's population was 206,518 at the 2020 census, also making it the second-most populous city in New England after Boston. Worcester is approximately 40 miles (64 km) west of Boston, 50 miles (80 km) east of Springfield and 40 miles (64 km) north-northwest of Providence. Due to its location near the geographic center of Massachusetts, Worcester is known as the "Heart of the Commonwealth"; a heart is the official symbol of the city. Worcester is the historical seat of Worcester County in central Massachusetts.