Poston is an unincorporated community and census-designated place (CDP) in La Paz County, Arizona, United States, in the Parker Valley.

During World War II, Poston was the site of the Poston War Relocation Center, one of the United States' largest Japanese-American internment camps, where over 17,000 Japanese-Americans were held over a three-year period.

Poston is located in western La Paz County, in the Parker Valley at 33°59′25″N 114°24′4″W / 33.99028°N 114.40111°W / 33.99028; -114.40111 (33.990348, -114.401052).

[3] It is 3 miles (5 km) east of the Colorado River, which forms the state border with California.

According to the United States Census Bureau, the Poston CDP has a total area of 1.4 square miles (3.6 km2), all land.