The courthouse has served as the cornerstone of the justice system in Maricopa County since its construction in 1929.
The Maricopa County Courthouse and Phoenix City Hall stand on the same plot of land as the original courthouse, which was built in 1884. For more than 40 years, the original courthouse stood out as an architectural landmark in a city that was dominated at the turn of the nineteenth century by largely non-descriptive low-rise frame buildings.
The original 1884 courthouse was built using adobe brick and constructions methods, as was common at the time. Prior to air conditioning, adobe bricks, often made on-site, worked to cool buildings by spreading heat away from the buildings core. The original courthouse also had a clock tower, as did many nineteenth-century municipal buildings, to serve as a master clock for transportation systems--in this case Phoenix's early trolley system.
As Phoenix boomed in the 1920s, civic leaders, including the judges who worked at the courthouse, questioned whether the courthouse was adequate to the many demands placed on it, including court functions, administrative offices, and a jail. In 1927, Maricopa County Voters endorsed constructing a new, more modern courthouse, and demolishing the original. At the same time the City of Phoenix was busy planning its ambitious future, and sought a new City Hall as well. As a result of the vote, the City and County were able to merge their respective administrative apparatus into a single building the covered an entire block--along Washington Street between 1st and 2nd Avenues. The Maricopa County Courthouse and Phoenix City Hall opened in 1929.
The Maricopa County Courthouse gained national notice in 1963 with the criminal trial of Ernesto Miranda. His legal case against the State of Arizona progressed to the Supreme Court of the United States in 1966. The Miranda Rights law regarding self-incrimination arose as a result of this Supreme Court verdict. The Maricopa County Courthouse received its entry in the National Registry of Historic Sites in 1988 due to the magnitude of this court case.