| Clue | Source | Date |
|---|---|---|
| Standard first down distance | ||
| Distance for a first down | New York Times | 30 Mar 2021 |
| *First down distance | Wall Street Journal | 25 Apr 2017 |
| Goal on a first down | New York Times | 19 Jun 2016 |
| Goal on a first down | ||
| First-down distance in football | Newsday | 02 Nov 2015 |
| First-down distance in football | ||
| Thirty feet | ||
| Thirty feet | ||
| Important football distance | ||
| Important football distance | ||
| First-down requisite | ||
| First-down requirement |