The Costa Mesa Historical Society offers tours of this historic adobe structure which is believed to be nearly 200 years old. Built sometime between 1817 and 1823, Diego Sepulveda Adobe is the second oldest building still standing in Orange County. Restored during the 1960s, the adobe structure is now home to a small history museum. The adobe structure contains four rooms that represent major periods in the history of the region.
The committee tasked with restoring the structure and operating the museum evolved into the Costa Mesa Historical Society. Visitors will also want to visit the new headquarters and larger museum operated by the society at 1870 Anaheim Ave.