<p>Map of districts of the Massachusetts state senate apportioned in 1876. The map includes 1885 population information. The location of the 5th Middlesex senate district is highlighted in red.
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Acts and Resolves of the Massachusetts General Court, <a rel="nofollow" class="external text" href="https://archives.lib.state.ma.us/handle/2452/89814">1876 Chap. 0190</a>. An Act To Divide The Commonwealth Into Forty Districts For The Choice Of Senators: "...The towns of Acton, Ashby, Ayer, Boxborough, Carlisle, Chelmsford, Concord, Dracut, Dunstable, Groton, Hudson, Lincoln, Littleton, Maynard, Pepperell, Shirley, Stow, Sudbury, Townsend, Tyngsborough and Westford, shall constitute a district, to be known as the Fifth Middlesex District...."
Rand, Avery &amp; Co.
<a rel="nofollow" class="external free" href="https://malegislature.gov/Redistricting/HistoricDistricts/Senate">https://malegislature.gov/Redistricting/HistoricDistricts/Senate</a>