Pomeroy is a city in Calhoun County, Iowa, United States. The population was 662 at the 2010 census.
On July 6, 1893, Pomeroy was struck by a tornado that was later estimated to be F5 on the Fujita scale. With a damage path 500 yards (460 m) wide and 55 miles (89 km) long, the tornado destroyed about 80% of the homes in Pomeroy. The tornado killed 71 people and injured 200.
In 1910, Pomeroy was the birthplace of Gordon Prange, who became Chief Historian in General Douglas MacArthur's staff and wrote the manuscript At Dawn We Slept, The Untold Story Of Pearl Harbor, the basis for the film Tora! Tora! Tora!.