Colorado - Criteria: C (architecture/engineering)
| Riede's City Bakery |
| Rifle Bridge |
| Rim Rock Drive Historic District |
| Rimrock School |
| Rio Grande Engine No. 168 |
| Rio Grande Southern Railroad Derrick Car |
| Rio Grande Southern Railroad, Motor No. 2 |
| Rio Grande Southern Railroad, Motor No. 6 |
| Rio Grande Southern Railroad Trout Lake Water Tank |
| Rito Seco Creek Culvert |
| Riverside Cemetery |
| Robertson, T. H., House |
| Robidoux, M.J. Lavina, House |
| Robinson House |
| Robinson House |
| Robison Mansion |
| Rock Creek Stage Station |
| Rock Island Snow Plow No. 95580 |
| Rockland Community Church and Cemetery |
| Rocky Ford Post Office |
| Rocky Mountain Bank Note Company Building |
| Rocky Mountain Lake Park |
| Rocky Mountain National Park Administration Building |
| Rocky Mountain National Park Utility Area Historic District |
| Romano, Samuel and Albina, House |
| Romeo Block |
| Rood Candy Company Building |
| Rooney Ranch |
| Root, Amos H., Building |
| Roselawn Cemetery |
| Rosemount |
| Ross-Broadway Branch, Denver Public Library |
| Rouch Gulch Bridge |
| Rourke, Eugene, House |
| Roxborough State Park Archaeological District |
| Royal Gorge Bridge and Incline Railway |
| Russell-Graves House |
| Russell Gulch I.O.O.F. Hall No. 47-Wagner and Askew |
| Ruth Memorial Methodist Episcopal Church |
| Sacred Heart Catholic Church |
| Sacred Heart Church |
| Sacred Heart Orphanage |
| Saddlehorn Caretaker's House and Garage |
| Saddlehorn Comfort Station |
| Saddlehorn Utility Area Historic District |
| Saguache Downtown Historic District |
| Saguache School and Jail Buildings |
| Saint Philomena Catholic Parish School |
| Salazar, A.A., House |
| Salina School |
| Salt Works Ranch |
| San Luis Bridge |
| San Luis Southern Railway Trestle |
| Santa Fe Avenue Bridge |
| Santa Fe Railway Manzanola Depot |
| Santa Fe Railway Water Tank |
| Sargents Water Tank, Denver and Rio Grande Railroad, Western Line |
| Satank Bridge |
| Schleier, George, Mansion |
| Schlessinger House |
| Schlichter, E.A., House |
| Schmidt, George, House |
| Sciumbato, Daniel, Grocery Store |
| Second Midland School |
| Sedgwick County Courthouse |
| Serpents Trail |
| Sevenmile Bridge |
| Seventeen Mile House |
| Shadow Mountain Lookout |
| Shadow Mountain Trail |
| Shaffer, Henry K. and Mary E., House |
| Sheedy Mansion |
| Sheely Bridge |
| Shenandoah-Dives Mill |
| Sherman and Ross Block Building |
| Shilling-Lamb House |
| Shirley Hotel |
| Shove Memorial Chapel |
| Shrine of the Sun |
| Silver Plume Depot |
| Sinclaire, Reginald, House |
| Sixth Avenue Community Church |
| Slate Creek Bridge |
| SLW Ranch |
| Smith-Elisha House |
| Smith-Eslick Cottage Court |
| Smith House |
| Smith, Milo A., House |
| Smith, Pierce T., House |
| Smith's Irrigation Ditch |
| Smith, William, House |
| Smuggler Mine |
| Smuggler-Union Hydroelectric Power Plant |
| Snogo Snow Plow |
| South Canon Bridge |
| South Marion Street Parkway |
| South Park Community Church |
| South Platte River Bridge |
| South Platte River Bridges |
| South Side-Baker Historic District |
Data from United States Park Service and Wikidata
