Diego Sepúlveda Adobe

The Diego Sepúlveda Adobe (sometimes known as the Costa Mesa Estancia or the Santa Ana Estancia) is an adobe structure built between 1817 and 1823 to house the mayordomo and herdsmen who tended the cattle and horses from nearby Mission San Juan Capistrano. Strategically situated on the banks of the Santa Ana River some six leguas (Spanish Leagues) north of the parent mission, the way-station also served as a lookout post when the French privateer Hipólito Bouchard attacked San Juan Capistrano on December 14, 1818. By 1820 the building and its surrounding lands became an official estancia (station), after which padres from the mission would visit regularly to bring "spiritual food" to the faithful.

The Adobe and its surrounding property (a portion of the Rancho Santiago de Santa Ana) were deeded to Diego Sepúlveda (a former alcalde of the Pueblo of Los Angeles) around 1868. The Adobe, which has been restored to its original style, using original construction methods, is the second oldest building still standing in Orange County, after San Juan's "Serra's Chapel." Today the facility is maintained by the Costa Mesa Historical Society as a museum.