Census Counties in Illinois Official U.S. Census Bureau and federal geographic directory listings. Showing 2 total records. Classification: Cities & Towns CDPs Counties Subdivisions ZIP Codes Features States State: Alabama Alaska American Samoa Arizona Arkansas California Colorado Connecticut Delaware District of Columbia Florida Georgia Guam Hawaii Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Northern Mariana Islands Ohio Oklahoma Oregon Pennsylvania Puerto Rico Rhode Island South Carolina South Dakota Tennessee Texas Utah Vermont Virgin Islands Virginia Washington West Virginia Wisconsin Wyoming Index A–Z: All A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Entity Name Classification Location / State GEOID Land Area Adams County County Illinois (IL) 17001 855.15 sq mi Alexander County County Illinois (IL) 17003 235.39 sq mi
