Built in 1921 at a cost of $135,000, a Spanish Colonial structure, affectionately known as “Old Main,” served as the Casa Grande district’s only high school for 76 years, Casa Grande Union High School. The building included a gymnasium, added in 1936, which is the only known adobe gymnasium in the state. Construction of the adobe structure was done using on-site earth to make 30,000 adobe bricks, and the manufacturing of the gym walls created much-needed jobs in Casa Grande’s deflated economy during the Depression years.
In 1997, the city stepped forward to find a new use for the building when plans were made to move the school to a different site. The structure was rehabilitated with a modern interior while restoring the original exterior with the assistance of a Heritage Fund Grant. The acquisition, rehabilitation, and adaptive reuse of the high school for a new city hall was completed at the cost of over $4 million.
The building now houses several key city departments, including the city manager’s office, city attorney’s office, the planning and zoning department, and the city clerk’s office. The building originally used for Casa Grande’s City Hall prior to its current site is now utilized as the Casa Grande Main Library.