Origionally named San Dionisio by Father Kino in 1700, his 1701 map shows the place as Doonysio or San Dionysio. In 1775 Father Francisco Graces established a mission in the area called 'Pueblo de la Concepcion', which was later destroyed. In 1854, Poston surveyed the city and sold the plans and land for $10,000. He registered the community as Colorado City and a post office was established there. The name was changed to Arizona (in New Mexico Territory) in 1858. However, after the destructive 1862 flood, the new post office and community (on higher ground) were named Yuma--for Fort Yuma--in 1866. Although the name reverted to Arizona City in 1869, the territorial legislature made Yuma official in 1873.