| Mark | Athlete | School | Year | Meet |
|---|
| 46.07 | Sophia Berry | Loyola Sacred Heart (B) | 10 | 6B/13C District Meet |
| 46.57 | Caidance Merecki | Huntley Project (B) | 11 | Al Walker Memorial Meet |
| 46.69 | Ava White | Superior (B) | 9 | Russ Plicher Western Top 10 |
| 46.78 | Allison Gama | Loyola Sacred Heart (B) | 10 | Russ Plicher Western Top 10 |
| 47.66 | Maddison Akins | Huntley Project (B) | 12 | 2025 Midland Roundtable Top 10 |
| 48.07 | Natalie Anderson | Darby (B) | 11 | Western B/C Divisional |
| 48.09 | Kalli Tuma | Plains (B) | 11 | Western B/C Divisional |
| 48.18 | Jaycee Luse | Cut Bank (B) | 11 | Northern B Divisional |
| 48.40 | Harper Morris | Lone Peak (B) | 11 | 5B/12C District Meet |