Kennett Square is a borough in Chester County, Pennsylvania, United States. It is known as the Mushroom Capital of the World because mushroom farming in the region produces over a million pounds of mushrooms a year. To celebrate this heritage, Kennett Square has an annual Mushroom Festival, where the town shuts down to have a parade, tour mushroom farms, and buy and sell food and other goods. It is also home to the corporate headquarters of Genesis HealthCare which administers elderly care facilities. Its population was 5,273 at the 2000 census.