| * Click on CENTER for graphical tier information | ||
| ZLC (ZLC 1) | ||
| FIRST TIER | ZDV / ZLA / ZMP / ZOA/ ZSE / (Canadian .. CYYC / CYEG) | |
| SECOND TIER | ZAB / ZAU / ZKC / ZOB | |
| * Click on CENTER for graphical tier information | ||
| ZLC (ZLC 1) | ||
| FIRST TIER | ZDV / ZLA / ZMP / ZOA/ ZSE / (Canadian .. CYYC / CYEG) | |
| SECOND TIER | ZAB / ZAU / ZKC / ZOB | |