Winthrop is a city in Suffolk County, Massachusetts, United States. The population was 19,316 at the 2020 census. Winthrop is an ocean-side suburban community in Greater Boston situated at the north entrance to Boston Harbor, close to Logan International Airport. It is located on a peninsula, 1.6 square miles in area, connected to Revere by a narrow isthmus and to East Boston by a bridge over the harbor inlet to the Belle Isle Marsh Reservation. Settled in 1630, Winthrop is one of the oldest communities in the United States. It is also one of the smallest and most densely populated municipalities in Massachusetts. It is one of the four cities that comprise Suffolk County. It is the southernmost part of the North Shore, with a 7-mile shoreline that provides views of the Atlantic Ocean to the east and of the Boston skyline to the west.
In 2005, the Town of Winthrop voted to change its governance from a representative town meeting adopted in 1920 to a council-manager form of government. Under Massachusetts law, as of 2006 when the new Town Charter took effect, Winthrop became de jure a city. However, it is one of thirteen cities in Massachusetts that chose to remain known as a 'town.'