A history of Chelmsford, Massachusetts, from 1655 to 1970 is presented. Written as an historiography exercise by students at Chelmsford High School, the study is intended to acquaint residents and students of Chelmsford with the town's past and its relationship with surrounding communities and the United States. Chapter one, "A Colonial Settlement Develops," describes geographic features and records Chelmsford's economic, political, and social development into a typical Puritan community. Chapter two, "Chelmsford Prepares for Independence," provides information on the town's prerevolutionary political activities and on its war experience. Chapter three, "Chelmsford at the Edge of Industrial America," chronicles the town's economic development during and immediately following the Civil War, at which time Chelmsford lost much of its most promising industry to larger towns. Chapter four, "Twentieth Century Chelmsford," describes the town's "coming of age" with the post World War II growth in defense and space industries. The authors conclude that Chelmsford presently is a mature suburban community facing the continuing task of preserving and improving its quality of life. A postscript, bibliography, and summaries of each chapter are included. (Author/DB)