| John Williams's efforts: | From | Age | Date | Finish Time |
|---|---|---|---|---|
| Quad Rock 2025 (Quad Rock 25) | Colorado, US | 39 | Saturday, May 10, 2025 | Not yet started |
| Red Feather Trail Jamboree 2024 50K | Colorado, US | 38 | Saturday, September 21, 2024 | 06:43:07.00 |
| Quad Rock 2021 (Quad Rock 50) | Colorado, US | 35 | Saturday, May 8, 2021 | 12:54:47.00 |
| Quad Rock 2017 | Colorado, US | 31 | Saturday, May 13, 2017 | DNF |