Illinois - Area of significance: Engineering
| Airtight Bridge |
| Alternate Route 66, Wilmington to Joliet |
| Armour's Warehouse |
| Auditorium Building, Roosevelt University |
| Babylon Bend Bridge |
| Baha'i Temple |
| Barber-Colman Company Historic District |
| Bernadotte Bridge |
| Blakeman Bridge |
| Bolivia Road Bridge |
| Brandon Road Lock and Dam Historic District |
| Bridge at Thirteenth Street |
| Buckeye Bridge |
| Buffalo Grove Lime Kiln |
| Buildings at 860-880 Lake Shore Drive |
| Camelback Bridge |
| Catlow Theatre |
| Cemetery Road Bridge |
| Central Park Theater |
| Cermak Road Bridge Historic District |
| Chain of Rocks Bridge |
| Chapin and Gore Building |
| Chicago Avenue Water Tower and Pumping Station |
| Chicago, Burlington, & Quincy Roundhouse and Locomotive Shop |
| Chicago Harbor Lighthouse |
| Chicago Sanitary and Ship Canal Historic District |
| Dresden Island Lock and Dam Historic District |
| Duncan Mills Bridge |
| Embarras River Bridge |
| Fall Creek Stone Arch Bridge |
| Fifteenth Street and Oklahoma Avenue Brick Street |
| Fisher Building |
| Fountain Creek Bridge |
| General Dean Suspension Bridge |
| Gold Coast Historic District |
| Griggsville Landing Lime Kiln |
| Hawes, J. H., Elevator |
| Hazen Bridge |
| Hennepin Canal Historic District |
| Hotel Baker |
| Illinois and Michigan Canal |
| Illinois Central Railroad Water Tower and Pump House |
| Illinois Iron Furnace |
| Illinois Route 4-North of Auburn |
| Indian Ford Bridge |
| Kehilath Anshe Ma'ariv Synagogue |
| La Grange Lock and Dam Historic District |
| Lock and Dam No. 15 Historic District |
| Lock and Dam No. 18 Historic District |
| Lockport Lock, Dam and Power House Historic District |
| London Mills Bridge |
| Lyndon Bridge |
| Manhattan Building |
| Marseilles Lock and Dam Historic District |
| Mary's River Covered Bridge |
| Old Colony Buildings |
| Old Stone Arch Bridge |
| Old Stone Arch, National Road |
| Otis Elevator Company Factory Building |
| Paxton Water Tower and Pump House |
| Peoria Lock and Dam Historic District |
| Peoria Mineral Springs |
| Peoria Waterworks |
| Red Covered Bridge |
| Rock Island Arsenal |
| Route 66 by Carpenter Park |
| Route 66, Cayuga to Chenoa |
| Route 66, Girard to Nilwood |
| Route 66, Litchfield to Mount Olive |
| Seville Bridge |
| Sixth, Seventh, and Tenth Street Stone Arch Bridges |
| Starved Rock Lock and Dam Historic District |
| Stone Arch Bridge |
| Stone Quarry Bridge |
| Sugar Creek Covered Bridge |
| Tallman, Horace M., House |
| Tartar's Ferry Bridge |
| Third St. Bridge |
| Thompson Mill Covered Bridge |
| U-505 (IX C U-Boat) |
| University of Illinois Observatory |
| US Army Aircraft C-53-DO-41-20124 |
| US ARMY Aircraft P-51D-25NA 44-73287 |
| Waltmire Bridge |
| Warm Air Research House |
| Western Springs Water Tower |
| West Water Tower and Ground Storage Tank |
| White Hall Foundry |
| Will County Historical Society Headquarters |
| Wooden Alley |
Data from United States Park Service and Wikidata
