| Clue | Source | Date |
|---|---|---|
| Timberland limits | Newsday | 30 Mar 2025 |
| Natural boundaries | LA Times Daily | 08 Jun 2017 |
| Natural boundaries | The Washington Post | 08 Jun 2017 |
| Natural boundaries | ||
| Tundra borders | Thomas Joseph | 27 Aug 2016 |
| Timberland limits | Newsday | 10 Jan 2016 |
| Mountain boundaries | ||
| Mountain boundaries |