(October 23, 1810 – May 18, 1848) was one of the earliest mixed-race U.S. citizens in California and a highly successful, enterprising businessman. He was a West Indian immigrant of African Cuban, possibly Carib, Danish and Jewish ancestry. William Alexander Leidesdorff, Jr. became a United States citizen in New Orleans in 1834. He migrated to California in 1841, then under Mexican rule, settling in Yerba Buena (San Francisco), a village of about 30 European-Mexican families.
He became a Mexican citizen in 1844 and received a land grant from the Mexican government, 8 Spanish leagues, or 35,500 acres (144 km2) south of the American River, known as Rancho Rio de los Americanos. He served as US Vice Consul to Mexico at the Port of San Francisco beginning in 1845. Leidesdorff was Presdident of the San Francisco school board and also elected as City Treasurer. Shortly before Leidesdorff’s death, vast amounts of gold were officially reported on his Rancho Rio De los Americanos. By the time his estate was auctioned off in 1856, it was worth more than $1,445,000, not including vast quantities of gold mined upon his land.
International Leidesdorff Bicentennial Celebrations will feature the “Golden Legacy of William Alexander Leidesdorff, Jr.” On October 22, 2011 on his native isle of St. Croix, U.S. Virgin Islands, a special event will highlight the season of celebrations.