The City Square State Park is n urban park in Charlestown, Massachusetts that is operated as a part of the Massachusetts state parks system under the Massachusetts Department of Conservation and Recreation. It covers one acre and is located at the very site of the historic Market Square.

The City Square State Park marks the site of a very historic area in Massachusetts. In 1629, it became the location of the Market Square which started its heritage of being a vital gathering place since the early days of the colony. It was largely developed through the years, all of which were proven necessary what with the continuous growth and modernization of the area.

Visitors of the City Square State Park today can enjoy various activities at the park including picnicking as well as attending several events that are usually held there.