Henry County, situated in Northwestern Illinois and just 16 miles from the Mississippi River - the boundary between Illinois and Iowa, had a populace of 51,020 in 2000. The county spans over an area of 823.21 square miles. The official headquarters of Henry County, Illinois can be found at 307 W Center St Rm 198, Cambridge, Illinois, 61238, United States, operating with a workforce of 185 employees.