Delphi Courthouse Square Historic District

The Delphi Courthouse Square Historic District in Delphi, Indiana is a 23-acre (9.3 ha) area roughly bounded by Monroe, Main, Market and Indiana Streets. It was listed on the National Register of Historic Places in 2010. It includes Italianate architecture and Classical Revival architecture and work by Elmer Dunlap among its 31 contributing buildings.

William Wilson donated 100 acres (40 ha) along Deer Creek for the town. The Indian mill sites located along the Creek made this a valuable site. Samuel Milroy lead the effort to make Delphi the county seat in May 1828. The nearby swamps meant that malaria, as endemic and the town grew slowly. The first permanent settler on record was Henry Robinson. With help from his family, the first log cabin was erected January 8, 1825, just south of Deer Creek on what is now known as "the hill" (later referred to as Robinson's hill). Daniel Baum and family also established their cabin on "Robinson's hill" where they started the first tavern "inn" that was frequented by settlers that passed through via the Indiana trail, which crossed Deer Creek just below their cabin.

The Wabash River, located north and west of Delphi, provided an excellent travel route for early settlers. Thus Delphi received its initial thrust under leadership when French Canadian traders from the north and settlers from Ohio and Kentucky came to this area to obtain possession of land and trade on the Wabash River. Ephraim Chamberlain purchased the first land in this township on February 17, 1824.

In 1826, Wabash and Erie Canal opened trade to the east and southwest. The town experienced new growth. With the advent of rail transportation the canal was put our of business with the boat in 1850, lost when the aqueduct over Deer Creek collapsed. The railroad arrived in Delphi in 1856. The railroad systems, which passed through Delphi, were the Norfolk and Western, Monon, and the Louisville and Nashville Railroad. The Fort Wayne-Wabash traction interurban line passed through Delphi in 1904. The interurban end when the motorbus was introduced.