The Old Orange County Courthouse in Santa Ana, California—the county seat of Orange County—is a Richardsonian Romanesque monolith of steel, cement, and brick clad in Arizona red sandstone (with a foundation clad in Temecula granite).
It was dedicated in 1901, just 12 years after the establishment of Orange County (having split off from Los Angeles County). That makes it Southern California's oldest county court building—now recognized as a historic landmark on both the state and federal levels.