Poston is a census-designated place in La Paz County, Arizona, United States, in Parker Valley. The population was 285 at the 2010 census. ​​

 

During World War II, Poston was the site of the Poston War Relocation Center, which was one of the United States' largest Japanese-American internment camps, where over 17,000 Japanese-Americans were held over a three-year period. The camp sites are now home to a monument dedicated to those interned there.