Plymouth Downtown Historic District is a national historic district located in Plymouth, Marshall County, Indiana, United States. The district encompasses 47 contributing buildings and one contributing structure in the central business district of Plymouth. It developed between about 1870 and 1940, and includes examples of Italianate, Romanesque Revival, and Colonial Revival style architecture. Located in the district is the separately listed Plymouth Fire Station. Other notable buildings include the Montgomery Ward Building (1929), Metsker Block (c. 1910), Rentschler Building (1910), Early Plymouth Post Office (1884), First National Bank-Plymouth City Hall (1879, 1916), Packard Bank Block (1879), Simons Building (1895), Wheeler Block (c. 1865), Bank Block (c. 1880), Bank Block-Masonic Tem