| 1859 | — | Members of Capt. W. F. Raynolds’ Yellowstone Expedition visit Bear Lodge (Devils Tower). |
| 1875 | — | U.S. Geological Survey visits formation. Name changed from Bear Lodge to Devils Tower. |
| 1892 | — | Area established as forest reserve. Senator Warren introduces bill to establish Devils Tower National Park. |
| 1893 | — | William Rogers and Willard Ripley make first ascent of Tower by ladder. |
| 1906 | — | President Theodore Roosevelt establishes Devils Tower as the first national monument. |
| 1930 | — | First full-time custodian appointed for monument. |
| 1933-41 | — | Area developed by Civilian Conservation Corps and other agencies in cooperation with the National Park Service. |
| 1937 | — | Fritz Wiessner and party first ascent of Tower by mountain-climbing techniques. |
| 1954 | — | Monument visitation passes 100,000 mark. |
| 1956 | — | Golden Anniversary of Devils Tower National Monument observed. |
| 1956 | — | 100th Anniversary of birth of Theodore Roosevelt. |
| 1963 | — | 1000th ascent of the Tower. |
| 1970 | — | 2000th ascent of the Tower. |
| 1973 | — | 3000th ascent of the Tower. |
| 1975 | — | 4000th ascent of the Tower. |
| 1975-76 | — | Reenactment of 1893 Flag Raising. |