Illinois - Criteria: A (event)
| Library Hall |
| Lincoln Branch Peoria Public Library |
| Lincoln Colored Home |
| Lincoln Courthouse Square Historic District |
| Lincoln Park |
| Lincoln Park Lily Pool |
| Lincoln Park, South Pond Refectory |
| Lincoln Public Library |
| Linden Avenue Terminal |
| Lind, Jenny, Chapel |
| Litchfield Public Library |
| Little Brick House |
| Livingston County Courthouse |
| Lock and Dam No. 13 Historic District |
| Lock and Dam No. 15 Historic District |
| Lock and Dam No. 17 Historic District |
| Lock and Dam No. 18 Historic District |
| Lock and Dam No. 21 Historic District |
| Lockport Historic District |
| Lockport Lock, Dam and Power House Historic District |
| Loeb, Ernest, House |
| London Mills Bridge |
| Lone Tree School |
| Loop Retail Historic District |
| Louisville and Nashville Depot |
| Lou Mitchell's Restaurant |
| Lowell Park |
| Lumpkin Heights and Elm Ridge Subdivision Historic District |
| Macktown Historic District |
| Macomb Courthouse Square historic District |
| Madison Theatre |
| Magill House |
| Maid-Rite Sandwich Shop |
| Main Street Historic District |
| Majestic Theatre |
| Malvern Roller Mill |
| Manly-McCann House |
| Manske-Niemann Farm |
| Maple Court Apartments |
| Marine Chapter House |
| Marion Veterans Administration Hospital Historic District |
| Marissa Academy |
| Mark, Caroline, House |
| Marseilles Hydro Plant |
| Marseilles Lock and Dam Historic District |
| Marshall Business Historic District |
| Marshall Field and Company Store |
| Marshall Field Company Store |
| Martin, Pierre, House |
| Martin, Sarah, House |
| Mary's River Covered Bridge |
| Marywood Academy |
| Massie Variety Store |
| Maxwell-Briscoe Automobile Company Showroom |
| Mayfair Apartments |
| Maynard, Isaac N., Rowhouses |
| Mazon Creek Fossil Beds |
| McAuley School District No. 27 |
| McGovney-Yunker Farmstead |
| Melwood Apartments |
| Memorial Hall |
| Memorial Washington Reformed Presbyterian Church |
| Mercer County Courthouse |
| Mercer County Fairgrounds |
| Mercer County Jail |
| Michigan-Lee Apartments |
| Michigan-Wacker Historic District |
| Middle Avenue Historic District |
| Midwest Athletic Club |
| Military Drill Hall and Men's Gymnasium |
| Millard, Sylvester, House |
| Millburn Historic District |
| Mineola Hotel |
| Miners Institute Building |
| Moats, William, Farm |
| Mobile and Ohio Railroad Depot |
| Moline Downtown Commercial Historic District |
| Monmouth Courthouse Commercial Historic District |
| Montgomery County Courthouse |
| Montgomery Ward Company Complex |
| Monticello Courthouse Square Historic District |
| Morgan County Courthouse |
| Morris Downtown Commercial Historic District |
| Morrison Main Street Historic District |
| Morris Wide Water Canal Boat Site |
| Morrow Plots, University of Illinois |
| Morton, J. Sterling, High School East Auditorium |
| Motor Row Historic District |
| Moultrie County Courthouse |
| Mound City National Cemetery |
| Mount Pulaski Courthouse |
| Mount Sterling Commercial Historic District |
| Mundelein College Skyscraper Building |
| Municipal Courts Building |
| Music Pavilion |
| Nachusa House |
| Naperville Historic District |
| Naples Archeological District |
| Narodni Sin |
| Natural History Building |
Data from United States Park Service and Wikidata
