Illinois - Significance region: Local
| Home Bank and Trust Company |
| Homestead, The |
| Hoopes-Cunningham Mansion |
| Hoopeston Carnegie Public Library |
| Hoopes, William, House |
| Hopkinson, Ambrose, House |
| Horseshoe Lake Mound and Village Site |
| Hotel Arthur |
| Hotel Aurora |
| Hotel Baker |
| Hotel Belleville |
| Hotel Del Prado |
| Hotel Kaskaskia |
| Hotel Plaza Site |
| Hotel Roodhouse |
| Hotel St. Benedict Flats |
| Hotel Stratford |
| Hotel Waukegan |
| Hotel Windermere East |
| House at 380 Chiltern Drive-Deerpath Hill Estates |
| House at 965 Castlegate Court-Deerpath Hill Estates |
| Hulburd, Joel H., House |
| Hull, William H., House |
| Humphrey, John, House |
| Hunter-Hattenburg House |
| Hunter, Lucinda, House |
| Hunt House |
| Hunziker Winery Site |
| IBM Building |
| Illinois Central Railroad and Toledo, Peoria, and Western Railroad Freight House |
| Illinois Central Railroad Depot |
| Illinois Central Railroad Depot |
| Illinois Central Railroad Depot |
| Illinois Central Railroad Passenger Depot |
| Illinois Central Railroad Water Tower and Pump House |
| Illinois Central Stone Arch Railroad Bridges |
| Illinois Industrial School for Girls |
| Illinois Iron Furnace |
| Illinois National Guard Armory |
| Illinois Route 4-North of Auburn |
| Illinois State Bank Building |
| Illinois Traction Building |
| Immaculata High School |
| Immanuel Evangelical Church |
| Immanuel Lutheran Church and Parsonage |
| Independence Park |
| Indian Boundary Park |
| Indian Hill Manor and Farm Historic District |
| Inland Steel Building |
| Inman Hotel |
| International Corset Company Building |
| International Harvester Building |
| International Harvester Showroom and Warehouse |
| International Tailoring Company Building |
| Irving, James B., House |
| Ives, Gideon, House |
| Jackson County Courthouse |
| Jackson Shore Apartments |
| Jacksonville Downtown Historic District |
| Jacksonville Historic District |
| Jacksonville Public Library |
| Jacoby, Lysander, House |
| James C. Curtis & Co. Building |
| James E. Plew Building |
| Jameson, H.D., House |
| Jarvis, William W., House |
| Jefferson Park |
| Jeffery-Cyril Historic District |
| Jehle, Louis, House |
| Jennings Ford Automobile Dealership |
| Jersey County Courthouse |
| Jerseyville Downtown Historic District |
| Jerseyville First Presbyterian Church |
| Jewish People's Institute |
| Johnson County Courthouse |
| Joilet YMCA |
| Joliet East Side Historic District |
| Joliet, Louis, Hotel |
| Joliet Steel Works |
| Jones House |
| Judah, Noble, Estate |
| Judd, C. H., House |
| Kamp Store |
| Kankakee County Courthouse |
| Kappa Delta Rho Fraternity House |
| Kappa Kappa Gamma Sorority House |
| Kappa Sigma Fraternity House |
| Karcher Hotel |
| Keithsburg Historic District |
| Kendall County Courthouse |
| Kenilworth Club |
| Kenwood Evangelical Church |
| Kewanee Hotel |
| Kewanee Public Library |
| Keys, Alvin S., House |
| Kickapoo Building |
| King, Moses, Brick and Tile Works |
| King, Patrick J., House |
| Kitchell Park |
| Klunk, Michael, Farmstead |
Data from United States Park Service and Wikidata
