- By 1945, Tsisqan 253 and Cole Snass Lamatai 259 from Oregon, and Thunder City 266 from Idaho, were split off from Area U to form Area Y:
 |
| Area Y (1945-46) |
Area Y (1947-48) | |
to Area 12-A* |
| Tsisqan 253 (from Area U) | 1946: Ump Quah 335 |
| Cole Snass Lamatai 259 (from Area U) | 1946: Wa-La-Moot-Kin 336 |
| Thunder City 266 (from Area U) | 1946: Tahoma 348 |
| 1/12/45: Kcumkum 285 | 3/27/47: Nanuk 355 |
| 6/4/45: Nez Perce 299 | 1947: Wilgus 361 |
| 6/5/45: Peta 300 | 7/25/47: Shoshoni 363 |
| 6/6/45: Moskwa 301 | 8/15/47: Lemonti Lemooto 365 |
| 6/20/45: Kelcema 305 | 6/48: Tillicum 392 |
| 6/12/45: Koo Ben Sho 311 | 8/48: Quetzel 400 |
| 10/19/45: Quilshan 325 |
|
|
|
|
*Sinawava 312 (Las Vegas, NV) was originally listed as part of Area Y, before being reassigned to the new
Area 12-A in 1946.
References: Area Lodges and Area Leaders, July 1945 Bulletin of the Order of the Arrow; Frank Dingwerth
- According to Frank Dingwerth, in 1948 these lodges (except for Nanuk 355, Shoshoni 363, and Lemonti Lemooto 365) met at Camp Black Mountain as Area Y.
- In September 1948, as part of the integration into the 12 Regions, the lodges of Area Y were reorganized as Region 11.
