| Mark | Athlete | School | Year | Meet |
|---|
| 48.66 | William Snell | Billings Central (A) | 11 | Midland Roundtable Top 10 |
| 49.20 | Evan Bennett | Hamilton (A) | 12 | Western A Divisional |
| 49.27 | Beck Whicker | Custer Co./Miles City (A) | 12 | Midland Roundtable Top 10 |
| 49.59 | Jack Phelps | Columbia Falls (A) | 12 | Western A Divisional |
| 50.16 | Colby Minton | Whitefish (A) | 10 | Western A Divisional |
| 50.19 | Joshua Eckhart | Hardin (A) | 12 | Eastern A Divisional |
| 50.48 | Preston McPherson | Whitefish (A) | 12 | Western A Divisional |
| 50.74 | Tayen Edmo | Ronan (A) | 12 | Western A Divisional |
| 51.20 | McKay Shobe | Fergus/Lewistown (A) | 11 | Eastern A Divisional |
| 51.27 | Samuel Jagodzinski | Billings Central (A) | 12 | MC John Polich Invite |
| 51.41 | Jake McCarthy | Hamilton (A) | 11 | Western A Divisional |
| 51.54 | Simon Douglas | Whitefish (A) | 12 | Last Chance Quad |
| 51.59 | Austin Savik | Bigfork (A) | 11 | Western A Divisional |
| 51.63 | Wade Qualtier | Ronan (A) | 12 | Nelson-Thomas ABC Meet |
| 51.64 | Solomon Morgan | Corvallis (A) | 12 | Ravalli County Invitational |
| 51.71 | Ethan Amick | Whitefish (A) | 12 | Western A Divisional |
| 51.86 | Jadon Persinger | Columbia Falls (A) | 12 | Western A Divisional |