State Representative Dan Sena represents the 37th Middlesex District, which includes Precincts 3, 4, 5, and 6A, of the town of Acton, the towns of Ayer, Boxborough and Shirley and Precinct 1 of the town of Groton, all in the county of Middlesex; and the town of Harvard, in the county of Worcester.

Dan follows in a line of distinguished legislators who fully committed themselves to making the 37th Middlesex District and the Commonwealth of Massachusetts better, fairer, stronger places for their residents. From 2003 to 2009, James B. Eldridge represented the 37th Middlesex District. Now-Senator Eldridge has had a tremendous role over the past two decades in serving his constituents and fighting for progressive legislation on issues like climate change, elections, criminal justice, and more. From 2009 to 2020, Jennifer E. Benson represented the 37th Middlesex District. Representative Benson was a leader on healthcare as House Chair of the Joint Committee on Health Care Financing, and now serves Massachusetts as President of the Alliance For Business Leadership