Kappa is a village in Woodford County, Illinois, United States. The population was 227 at the 2010 census, up from 170 in 2000. It is part of the Peoria, Illinois Metropolitan Statistical Area.

The Peoria Metropolitan Statistical Area, as defined by the United States Census Bureau, is an area consisting of six counties in Central Illinois, anchored by the city of Peoria. As of the 2020 census, the area had a population of 402,391. The City of Peoria, according to the 2020 US Census Bureau, has 113,150 people.