is a town in Providence County, Rhode Island, United States. The population was 28,195 at the 2000 census. Johnston is the site of the Clemence Irons House(1691) a stone-ender museum and the only landfill in Rhode Island. Incorporated on March 6, 1759, Johnston was named for the colonial attorney general, August Johnston.
According to the United States Census Bureau, the town has a total area of 24.4 mi² (63.1 km²). 23.7 mi² (61.3 km²) of it is land and 0.7 mi² (1.8 km²) of it (2.91%) is water.