The city of Northampton is the county seat of Hampshire County, Massachusetts, United States. As of the 2020 census, the population of Northampton (including its outer villages, Florence and Leeds) was 29,571.

Northampton is known as an academic, artistic, musical, and countercultural hub. It features a large politically liberal community along with numerous alternative health and intellectual organizations. Based on U.S. Census demographics, election returns, and other criteria, the website Epodunk rates Northampton as the most politically liberal medium-size city (population 25,000–99,000) in the United States. The city has a high proportion of residents who identify as gay and lesbian and a high number of same-sex households and is a popular destination for the LGBT community.

Northampton is part of the Pioneer Valley and is one of the northernmost cities in the Knowledge Corridor—a cross-state cultural and economic partnership with other Connecticut River Valley cities and towns. Northampton is part of the Springfield Metropolitan Area, one of western Massachusetts’s two separate metropolitan areas. It sits approximately 19 miles (31 km) north of the city of Springfield.

Northampton is home to Smith College, Hotel Northampton, Northampton High School, Smith Vocational and Agricultural High School, and the Clarke Schools for Hearing and Speech.

Northampton was known as “Norwottuck”, or “Nonotuck”, meaning “the midst of the river”, named by its original Pocumtuc inhabitants. According to various accounts, Northampton was given its present name by John A. King (1629–1703), one of the first white settlers in Northampton, or possibly in King’s honor, since it is supposed that he came to Massachusetts from Northampton, England, his birthplace.

The Pocumtuc confederacy occupied the Connecticut River Valley from what is now southern Vermont and New Hampshire into northern Connecticut. The Pocumtuc tribes were Algonquian and traditionally allied with the Mahican confederacy to the west. By 1606 an ongoing struggle between the Mahican and Iroquois confederacies led to direct attacks on the Pocumtuc by the Iroquoian Mohawk nation. The Mahican confederacy had been defeated by 1628, limiting Pocumtuc access to trade routes to the west. The area suffered a major smallpox epidemic in the 1630s following the arrival of Dutch traders in the Hudson Valley and New England settlers in the Massachusetts Bay Colony during the previous two decades. It was in this context that the land making up the bulk of modern Northampton was sold to settlers from Springfield in 1653.