St. Johns is a census-designated place (CDP) in Maricopa County, Arizona, United States, located in the Gila River Indian Community. The population was 476 at the 2010 census.
As of the census of 2010, there were 476 people residing in the CDP. The population density was 208.7 people per square mile. The racial makeup of the CDP was 2.94% White, 0.21% Black or African American, 94.96% Native American, 0.63% from other races, and 1.26% from two or more races. 3.99% of the population were Hispanic or Latino of any race.