| Marissa Koski's efforts: | From | Age | Date | Finish Time |
|---|---|---|---|---|
| Black Mountain Trail Races (50k) | California, US | 25 | Saturday, June 21, 2025 | 05:26:14.00 |
| 2015 Rattlesnake Ramble (Full Course) | 16 | Saturday, September 12, 2015 | 00:56:56.00 | |
| 2013 Rattlesnake Ramble (Full Course) | 14 | Saturday, November 9, 2013 | 00:52:39.00 | |
| 2012 Rattlesnake Ramble (Full Course) | 13 | Saturday, September 15, 2012 | 00:52:29.00 | |
| 2011 Rattlesnake Ramble (Kids Run) | 12 | Saturday, September 17, 2011 | 00:16:30.00 | |
| 2010 Rattlesnake Ramble (Kids Run) | 11 | Saturday, September 18, 2010 | 00:24:51.00 |