Livingston County is a county in the U.S. state of Illinois. In the 2020 census, 35,815 people lived there.[1] The county seat is Pontiac. [1]"QuickFacts: Livingston County, Illinois". United States Census Bureau. Retrieved August 11, 2023. This short article about a place or feature in the United States can be made longer. You can help Wikipedia by adding to it.