Illinois - Area of significance: Commerce
| Princeton North Main Street Historic District |
| Princeton South Main Street-Courthouse Square Historic District |
| Proctor Building |
| Produce Terminal Cold Storage Company Building |
| Pulsifer, Edward, House |
| Railway Exchange Building |
| Randecker's Hardware Store |
| Red Bud Historic District |
| Robinson-Bonnett Inn |
| Robinson, J. L., General Store |
| Rochelle Downtown Historic District |
| Rock Island Lines Passenger Station |
| Rogers, Col. Matthew, Building |
| Rohrbough, Calendar, House |
| Rose Hotel |
| Ross, Harvey Lee, House |
| Ruebel Hotel |
| Rutter Store |
| Saline Springs |
| Scales Mound Historic District |
| Schlosser, Frank, Complex |
| Schulze Baking Company Plant |
| Sears, Albert H., House |
| Sears, Roebuck and Company Complex |
| Seventh Street Commercial Historic District |
| Shabbona Hotel |
| Shelbyville Historic District |
| Sheridan Plaza Hotel |
| Singer Building |
| Soulsby Service Station |
| South Loop Printing House District |
| South Water Market |
| Spafford, Amos Catlin, House |
| Spring Valley House-Sulfur Springs Hotel |
| Standard Oil Gasoline Station |
| Starr Hotel |
| State Bank |
| State Bank Building |
| State Savings Loan and Trust |
| Stearns-Wadsworth House |
| St. Nicholas Hotel |
| Stolp Island Historic District |
| Stolp Woolen Mill Store |
| Stone Arch Bridge |
| Stony Island Trust and Savings Bank Building |
| Storkline Furniture Corporation Factory |
| Strand Hotel |
| Streibich Blacksmith Shop |
| Swift House |
| Taylor, Oscar, House |
| Taylorville Courthouse Square Historic District |
| Teich, Curt, and Company Building |
| The Hunt Club |
| Theurer-Wrigley House |
| United States Post Office-Chicago |
| Uptown Square Historic District |
| Urbana-Lincoln Hotel-Lincoln Square Mall |
| Vermont Historic District |
| Vriner's Confectionery |
| Warfield, William S., House |
| Warren Commercial Historic District |
| West Downtown Rockford Historic District |
| West Loop-LaSalle Street Historic District |
| West Loop-LaSalle Street Historic District |
| White Hall Historic District |
| Wholesale Florists Exchange |
| Will County Historical Society Headquarters |
| Wilmette Village Center Historic District |
Data from United States Park Service and Wikidata
