Windsor is an incorporated town in Sonoma County, California, United States. The town is 9 miles north of Santa Rosa and 63 miles north of San Francisco. The population was 26,801 as of the 2010 census. Windsor’s first European settlers arrived in 1851. In 1855, Hiram Lewis, a Pony Express rider, became the town’s first postmaster. He named the town Windsor because it reminded him of the grounds around Windsor Castle, a medieval castle from his home country of England. In 1855, a post office was established in Windsor. The following year, a business enterprise was built in eastern Windsor, which included a goods store, a shoe shop, a grocery and meat market, a saloon, a hotel, a boarding house, and two confectionery shops. The Northwestern Pacific Railroad was completed through the town in 1872, providing a faster and cheaper link to the Bay Area.