| Mark | Athlete | School | Year | Meet |
|---|
| 45.16 | Reagan Johnstone | Stevensville (A) | 9 | Western A Divisional |
| 46.23 | Ginger Bergland | Whitefish (A) | 9 | MCPS Invitational |
| 46.52 | Jenna Ellis | Hamilton (A) | 11 | Western A Divisional |
| 46.68 | Riley McCoy | Beaverhead Co./Dillon (A) | 12 | Nelson-Thomas ABC Meet |
| 47.15 | Blythe Armstrong | Fergus/Lewistown (A) | 11 | Midland Roundtable Top 10 |
| 47.37 | Scarlett Jones | Frenchtown (A) | 10 | Nelson-Thomas ABC Meet |
| 47.43 | Aubrey Korst | Hamilton (A) | 11 | Western A Divisional |
| 47.59 | Reine McCoy | Beaverhead Co./Dillon (A) | 10 | Western A Divisional |
| 48.21 | Kellyn Nelson | Polson (A) | 11 | Western A Divisional |
| 48.46 | Brynlee Tucker | Corvallis (A) | 9 | Western A Divisional |
| 48.47 | Perri Sloan | Custer Co./Miles City (A) | 10 | Billings Invite |
| 48.72 | Blake Hardy | Frenchtown (A) | 10 | Hamilton Bronc Invitational |
| 48.85 | Grace Hicks | Fergus/Lewistown (A) | 11 | Eastern A Divisional |
| 48.88 | Kate Allen | Corvallis (A) | 10 | Western A Divisional |
| 48.89 | Ava Graham | Beaverhead Co./Dillon (A) | 12 | Sapphire Twilight Meet |