Since 1864, Los Angeles attorneys Alfred Chapman and Andrew Glassell together and separately, held about 5,400 acres along both sides of the Santiago Creek. Water was the key factor for the location of their townsite. Glassell needed a spot he could irrigate, bringing water down from the Santa Ana Canyon and the quality of the soil may have influnced his choice. In the book, "Orange, The City 'Round The Plaza" by local historian Phil Brigandi, it states, "In 1873 the town had grown large enough to require a post office, so an application was sent to Washington. It was refused, however, as there was (and is) already a Richland, California in Sacramento County. Undaunted, the Richlanders proposed a new name - Orange. Brigandi explains three options as to how the name Orange was selected, "it was a good marketable name that suggested a prosperous, semi-tropical agricultural area. Second, there was already talk of creating an "Orange County" out of the southern end of Los Angeles County. Finally, the Glassell family once lived in Orange County, Virginia, so the name had a familiar ring. (In the same way, the Glassell family's old plantation had been called Richland.)" The city NEVER got it's name based on a poker game, that is an old myth.
The small town was incorporated on April 6, 1888 under the general laws of the State of California. Orange was the only city in Orange County to be planned and built around a Plaza and it earned it the nickname the Plaza City. Orange was the first developed town site to be served by the California Southern Railroad when the nation's second transcontinental rail line reached Orange County.
Old Towne Orange Historic District, a one square-mile around the original plaza contains many of the original structures built in the period after the City's incorporation. It remains a vibrant commercial district, containing Orange County's oldest operating bank and the oldest operating soda fountain. The Historic District was listed on the National Register of Historic Places in 1997 and is the largest National Register District in California. The Old Town Preservation Association is a non-profit organization dedicated to maintaining the district. Orange is unique among the region and the state in that it has the second largest concentration of historic buildings. A list of all of the buildings and sites in Orange appear in the National Register of Historic Places.