Liberty Courthouse Square Historic District is a national historic district located at Liberty, Union County, Indiana. The district encompasses 20 contributing buildings and 2 contributing objects in the central business district of Liberty and centered on the separately listed Union County Courthouse. It developed between about 1854 and 1938 and includes representative examples of Italianate, Romanesque Revival, Neoclassical, and Art Deco style architecture. Notable contributing buildings include the O'Toole Building (1936), Masonic Hall (c. 1860), Odd Fellows Building (c. 1854), Liberty Opera House (c. 1878), and Liberty Post Office (1937-1938).