US National Championship winners in men's 400-meter dash | |
|---|---|
| 1876-1979 Amateur Athletic Union |
|
| 1980-1992 The Athletics Congress |
|
| 1992 onwards USA Track & Field |
|
| Notes |
|
US National Championship winners in men's indoor 600-yard dash | |
|---|---|
| 1906–1979 Amateur Athletic Union |
|
| 1981–1992 The Athletics Congress |
|
| 1993–present USA Track & Field |
|
| Notes | *Distances have varied as follows: 600 yards (1906–1986), 500 meters (1987–1993) except 600 meters (odd numbered years since 2015) |
