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is a city in and the county seat of Butler County, Iowa, United States. The population was 1,006 at the 2000 census. Allison is home to the Butler County Fair. The city was named for U.S. Senator William Boyd Allison in 1881.
According to the United States Census Bureau, the city has a total area of 3.0 square miles (7.6 km²), all of it land.