As only a junior, Denver East High School's (CO) Arria Minor has dominated the 400m in 2018. She won the Great Southwest Classic in 52.50 and was third in the finals of the USATF Junior Outdoor Championships with a run of 52.25.
Her best run of the season came at the Colorado State Track and Field Championships when she ran 51.92 in the prelims. Although she finished second to Grandview High School's (CO) Lily Williams (53.85), her time in the finals remains a Colorado state meet record.
Along with Minor, three other girls have run sub-53 seconds in the 400m.
Check out the full very early 2019 girls 400m rankings below.