The Valley and range sequence-Southern Yuma County is a 3-Valley sequence of NW–by–SE trending block faulted valleys and mountains. About eleven major mountain ranges connect to each other in four, (mostly parallel), mountain sequences.
This regional parallel valley-mountain sequence ends at the Gila River valley at the north; to the south, it extends to the Gran Desierto de Altar of northwestern Mexico; the sequence is a remnant of the Basin and Range system.
The three valleys lay mostly between these perimeter mountain sequences.
| West Sequence North | W-Central block | E-Central block | East Sequence North |
|---|---|---|---|
| Gila River Valley | Gila River Valley | Gila River Valley | Gila River Valley |
| Gila Mountains (Yuma County) | Wellton Hills and Baker Peaks | Mohawk Mountains | Aztec Hills |
| Gila Mountains (Yuma County) | Copper Mountains | Mohawk Mountains | Aguila Mountains |
| Tinajas Altas Mountains and Butler Mountains) | W:Cabeza Prieta and Tule Mountains E:Sierra Pinta | Bryan Mountains and Antelope Hills | Granite Mountains (Arizona) |
| Tinajas Altas Mountains and Butler Mountains) | W:Cabeza Prieta and Tule Mountains E:Sierra Pinta | Bryan Mountains and Antelope Hills | xxxxxx |
| West Sequence South | W-Central block | E-Central block | East Sequence South |