The following maps of Dorchester are those most useful for property research. The Dorchester Historical Society owns copies, but many are available online at other institutions.
1831
A Map of the Towns of Dorchester and Milton
Edmund J. Baker
available online at The Norman B. Leventhal Map Center at the Boston Public Library
1850
Map of Dorchester, Mass.
Elbridge Whiting for S. Dwight Eaton (Old Colony R.R. Depot, Boston)
Tappan & Bradford’s Lithography, Boston
available online at The Norman B. Leventhal Map Center at the Boston Public Library
http://maps.bpl.org/id/11129
1858
Map of the County of Norfolk, Massachusetts
H.F. Walling
Published by Smith & Bumstead, Boston and New York
available online at Boston Public Library Leventhal Map Center
https://collections.leventhalmap.org/search/commonwealth:9s161933d
There are some missing sections in the BPL copy, so you could also try
1870
Boston. Engineering Dept. Plan of the Town of Dorchester available online at The Norman B. Leventhal Map Center at the Boston Public Library
1871
Harper & Brothers. Bird’s-eye view of Boston and surrounding area, Boston Public Library
1874
Atlas of the County of Suffolk, Massachusetts, Vol. 3rd including South Boston and Dorchester. Philadelphia: G.M. Hopkins & Co., 1874. Boston Public Library Leventhal Map Center
https://archives.lib.state.ma.us/handle/2452/206069
1884
Atlas of the County of Suffolk, Massachusetts, Vol. 3rd including South Boston and Dorchester. Philadelphia: Geo. W. & Walter S. Bromley, 1884. Leventhal Map Collection at the Boston Public Library online.
https://collections.leventhalmap.org/book_viewer/commonwealth:tt44pv533#1/1
In 1884, some of Dorchester appears on plates L and M of the Roxbury atlas
https://collections.leventhalmap.org/book_viewer/commonwealth:tt44pv58g#1/1
and on plate D of the South Boston atlas
https://collections.leventhalmap.org/search/commonwealth:tt44pv59r
1889
Atlas of the city of Boston. Vol. 5: Dorchester
Geo. W. & Walter S. Bromley
Philadelphia: G.W. Bromley & Co., 1889.
https://collections.leventhalmap.org/book_viewer/commonwealth:tt44pv65w#1/1
1890
Bird’s-eye view of Lower Mills. Boston Public Library
1890
Bird’s-eye view of Mattapan. Boston Public Library
1894
Atlas of the City of Boston: Volume 5: Dorchester, Mass. George W. and Walter S. Bromley
Philadelphia: Bromley, 1894
https://collections.leventhalmap.org/search/commonwealth:tt44pv843
or
1898
Atlas of the City of Boston, Vol. 5. Dorchester, Mass. George W. and Walter S. Bromley.. Philadelphia, G. W. Bromley & Co., 1898
https://collections.leventhalmap.org/search/commonwealth:tt44pv82j
or
1899
Atlas: Dorchester, West Roxbury, Brighton
J.P. Brown & Co.; L.J. Richards
Publisher: L.J. Richards, Boston
https://collections.leventhalmap.org/search/commonwealth:tt44pv800
1904
Atlas of the City of Boston, Vol. 5. Dorchester, Mass. George W. and Walter S. Bromley. Philadelphia: G.W. Bromley & Co., 1904
https://collections.leventhalmap.org/search/commonwealth:tt44pv94b
1910
Atlas of the City of Boston: Dorchester, Mass. George W. and Walter S. Bromley
Philadelphia: G.W. Bromley & Co., 1910
https://collections.leventhalmap.org/search/commonwealth:tt44pv886
1918
Atlas of the City of Boston: Dorchester. George W. and Walter S. Bromley.. Philadelphia: G. W. Bromley & Co., 1918
https://collections.leventhalmap.org/search/commonwealth:tt44pw04c
1933
Atlas of the City of Boston: Dorchester. George W. and Walter S. Bromley. Philadelphia: G. W. Bromley & Co., 1933
https://www.loc.gov/item/2008622000/
or
https://collections.leventhalmap.org/search/commonwealth:tt44pw849
or