Jersey County, Is., c. h. at Jerseyville. Bounded N. by Greene and E. by Macoupin co., S. by Madison co. and the Mississippi River, separating it from Missouri, and W. by the Illinois River, separating it from Calhoun co. Watered on the N. by a branch of the Illinois River.

Lake County, Is., c. h. at Little Fort. Bounded N. by Wisconsin, E. by Lake Michigan, S. by Cook, and W. by McHenry co. Watered by Des Plaines and Fox Rivers. Surface undulating, being mostly prairie land.