Knox County Courthouse in Center, Nebraska; seen from the southeast. The courthouse was built in 1934, and is listed in the National Register of Historic Places. – Ammodramus, Public domain – Wikimedia Commons Knox County is located in Nebraska. About 8,391 people live here (as of 2020). Between 2010 and 2020, the population declined from 8,701 to 8,391. The area covers about 2,952.0 square kilometers. The region is divided into 11 Municipalities and 2 Subregions. The region was founded in 1854. The name originates from Henry Knox (American general and Secretary of War) Knox County is county in Nebraska, United States. More information at www.co.knox.ne.us.