| Mark | Athlete | School | Year | Meet |
|---|
| 49.28 | John Daubert | Billings Senior (AA) | 12 | State AA Track Meet |
| 49.65 | Kyle Nickol | Helena Capital (AA) | 10 | Western AA Divisional |
| 49.92 | Chris Allen | Belgrade (AA) | 12 | Beaverhead Booster Meet |
| 50.29 | Alex Klatt | Billings Senior (AA) | 11 | State AA Track Meet |
| 50.44 | Michael Managhan | Flathead (AA) | 12 | State AA Track Meet |
| 50.72 | Tyler Roush | Billings West (AA) | 10 | Billings West Invitational |
| 50.84 | Alex Wambach | Billings West (AA) | 12 | Billings West Invitational |
| 50.87 | Thomas Neale | Billings Skyview (AA) | 12 | State AA Track Meet |
| 50.89 | Jacob Kvilhaug | Billings West (AA) | 11 | State AA Track Meet |
| 51.09 | Trey Cates | Great Falls CMR (AA) | 12 | Eastern AA Divisional |
| 51.13 | Logan Laird | Billings West (AA) | 10 | Swede Dahlberg Memorial |
| 51.48 | Colter Porter | Billings West (AA) | 11 | Eastern AA Divisional |
| 51.52 | Kyle Koszuta | Billings Skyview (AA) | 11 | Eastern AA Divisional |
| 51.53 | Nick Propp | Missoula Sentinel (AA) | 12 | Swede Dahlberg Memorial |
| 51.53 | Taylor Clark | Billings West (AA) | 11 | Eastern AA Divisional |
| 51.62 | Alex Mustard | Missoula Big Sky (AA) | 10 | Greg Rice City Meet |
| 51.64 | Zach Perrin | Flathead (AA) | 11 | Whitefish A.R.M. Invitational |
| 51.64 | Isaiah Collins | Great Falls CMR (AA) | 12 | CMR-Helena Dual |
| 51.87 | Kole Garitone | Billings West (AA) | 11 | Eastern AA Divisional |