| 1 | Katie Broderick SR | Dowling Catholic | 56.03 | Linn-Mar Aquatic Center | 09/14/2019 |
| 2 | Hayley Kimmel FR | Linn-Mar | 56.46 | Linn-Mar Aquatic Center | 10/19/2019 |
| 3 | Grace Frericks SO | Cedar Falls | 56.71 | Linn-Mar Aquatic Center | 10/19/2019 |
| 4 | Berit Quass SR | Dowling Catholic | 56.81 | Trail Point Aquatics & Wellness | 10/24/2019 |
| 5 | Scarlet Martin SO | Iowa City West | 56.94 | Mercer Park Aquatic Center and Scanlon Gym | 09/24/2019 |
| 6 | Annie Galvin JR | Ames | 57.27 | Linn-Mar Aquatic Center | 09/14/2019 |
| 7 | Sami Roemer SR | Bettendorf | 57.97 | Mercer Park Aquatic Center and Scanlon Gym | 09/21/2019 |
| 8 | Mary Martin JR | Dowling Catholic | 58.03 | Trail Point Aquatics & Wellness | 10/24/2019 |
| 9 | Maddie Grant SR | Dowling Catholic | 58.24 | Trail Point Aquatics & Wellness | 10/24/2019 |
| 10 | Aurora Roghair JR | Iowa City West | 58.34 | Holmes Swimming Pool | 10/01/2019 |
| 11 | Abby Rastetter JR | Johnston | 58.54 | Summit Middle School | 08/29/2019 |
| 12 | Julia Sweetman FR | Dowling Catholic | 58.67 | Trail Point Aquatics & Wellness | 10/24/2019 |
| 13 | Carly Weigel SR | Iowa City High | 58.75 | Mercer Park Aquatic Center and Scanlon Gym | 09/24/2019 |
| 14 | Abby Hala SO | Ames | 59.23 | Ames High School | 09/24/2019 |
| 15 | Abby McCorkle JR | Ames | 59.32 | Dowling Catholic High School | 10/15/2019 |
| 16 | Jessi Wigham FR | Waukee | 59.36 | Valley High School | 10/01/2019 |
| 17 | Sydney Jones JR | Cedar Rapids Washington | 59.41 | Lincoln High School | 09/28/2019 |
| 18 | Ellie Clark JR | Dowling Catholic | 59.43 | Dowling Catholic High School | 10/15/2019 |
| 19 | Alexis Henning SO | Ankeny | 59.50 | Trail Point Aquatics & Wellness | 10/15/2019 |
| 20 | Meghan Donald SO | Ames | 59.51 | Ames High School | 09/24/2019 |
| 21 | Mia Moulden JR | Ames | 59.64 | Ames High School | 09/24/2019 |
| 22 | Hope Cvrk JR | Sioux City North | 59.68 | Valley High School | 09/28/2019 |
| 23 | Kate MacLeod JR | Ames | 59.89 | Trail Point Aquatics & Wellness | 10/24/2019 |
| 24 | Olivia Frantum FR | Johnston | 1:00.07 | Trail Point Aquatics & Wellness | 10/15/2019 |
| 25 | Scout Bergwall SR | Ankeny | 1:00.12 | Trail Point Aquatics & Wellness | 10/15/2019 |
| 26 | Cecile Lorenzen JR | Des Moines Roosevelt | 1:00.26 | Roosevelt High School | 10/22/2019 |