London Government Offices County 825 Us Highway 42 NE Madison County Online Services. Your source for local government information. Named after James Madison, 4th President of the United States, Madison County is located in central Ohio between Columbus and Springfield. Primarily an agricultural area, 88% of the land consist of farms. Madison County ranks fourth in both soybean and corn production throughout the state of Ohio. Annually in September the Ohio State University hosts the Farm Science Review, one of the largest farm exhibitions in the world, at the Molly Caren Agricultural Center near London, Ohio. Madison County Attractions include Madison Lake State Park, the Red Brick Tavern, Rails to Trails, the Jonathan Alder Cabin, and the State and National Scenic River London OH Government Offices County Madison County Engineer www.co.madison.oh.us Business Reviews Madison County Engineer Testimonials