Humboldt was platted in 1868 and the first business on the city square was established in 1869. Town founder O.J. Tinker deeded two acres for a public square in 1871 and Humboldt was incorporated in 1873. The bandstand in the center of the City Square Park was built in 1912 and dedicated to Tinker's memory. Humboldt reached a peak population of 1,455 in 1930, and the built environment reflects this prosperity through modernization of existing buildings, as well as construction of several new buildings. Brick streets were laid in 1920. The auditorium was constructed as a Works Progress Administration (WPA) project in 1942 using concrete and locally quarried limestone. The buildings included in the historic district date from 1877 to 1947. The city square became the home of the Humboldt Fall Festival in 1921, followed by the Richardson County Fair in 1924. The square played a very important role in the development of Humboldt and continues to be a focal point in the community. The Humboldt Commercial Historic District was added to the National Register of Historic Places in 2005.