| Mark | Athlete | School | Year | Meet |
|---|
| 46.09 | Rileigh McGree | Butte Central (A) | 11 | State A |
| 46.15 | Hailey Ells | Whitefish (A) | 9 | State A |
| 46.34 | Olivia Lewis | Corvallis (A) | 9 | Western A Divisional |
| 46.78 | Ainsley Shipman | Beaverhead Co./Dillon (A) | 11 | Western A Divisional |
| 47.82 | Lauryn Petersen | Beaverhead Co./Dillon (A) | 11 | State A |
| 48.16 | Rylee Armstrong | Fergus/Lewistown (A) | 10 | Eastern A Divisional |
| 48.42 | Sydney Petersen | Beaverhead Co./Dillon (A) | 9 | Western A Divisional |
| 48.46 | Maeve Ingelfinger | Whitefish (A) | 9 | Western A Divisional |
| 48.61 | Sadie Filius | Havre (A) | 11 | State A |