City | State | 2026 Pop.↓ | Annual Change | Rank | Type |
|---|---|---|---|---|---|
| Denver | Colorado | 746,590 | 0.81% | 2 | City |
| Albuquerque | New Mexico | 555,119 | -0.26% | 3 | City |
| Colorado Springs | Colorado | 497,549 | 0.57% | 6 | City |
| Aurora | Colorado | 415,462 | 1.32% | 7 | City |
| Boise City | Idaho | 238,853 | 0.18% | 12 | City |
| Salt Lake City | Utah | 222,706 | 1.96% | 13 | City |
| Fort Collins | Colorado | 171,693 | 0.11% | 17 | City |
| Lakewood | Colorado | 157,210 | 0.18% | 18 | City |
| Thornton | Colorado | 149,318 | 1.05% | 19 | City |
| Meridian | Idaho | 148,009 | 3.51% | 20 | City |
| West Valley City | Utah | 137,047 | -0.32% | 21 | City |
| Nampa | Idaho | 124,426 | 3.36% | 24 | City |
| Arvada | Colorado | 122,391 | -0.41% | 25 | City |
| Billings | Montana | 122,295 | 0.87% | 26 | City |
| Las Cruces | New Mexico | 118,133 | 0.99% | 27 | City |
| West Jordan | Utah | 116,737 | -0.06% | 28 | City |
| Greeley | Colorado | 116,451 | 1.2% | 29 | City |
| Rio Rancho | New Mexico | 116,418 | 1.75% | 30 | City |
| Westminster | Colorado | 116,095 | -0.07% | 31 | City |
| Provo | Utah | 114,523 | 0% | 32 | City |
| St. George | Utah | 111,344 | 2.42% | 33 | City |
| Pueblo | Colorado | 110,269 | -0.12% | 35 | City |
| Centennial | Colorado | 109,178 | 0.48% | 36 | City |
| Boulder | Colorado | 105,220 | -0.44% | 38 | City |
| Highlands Ranch | Colorado | 102,527 | 0.36% | 40 | CDP |
| Longmont | Colorado | 100,211 | 0.1% | 41 | City |
| Lehi | Utah | 99,366 | 4.25% | 42 | City |
| Orem | Utah | 94,699 | -0.54% | 44 | City |
| Sandy | Utah | 91,360 | -1.11% | 45 | City |
| Santa Fe | New Mexico | 90,468 | 0.7% | 46 | City |
| Ogden | Utah | 89,987 | 0.53% | 47 | City |
| South Jordan | Utah | 89,666 | 2.34% | 48 | City |
| Castle Rock | Colorado | 86,094 | 2.72% | 49 | Town |
| Layton | Utah | 85,883 | 0.67% | 50 | City |
| Loveland | Colorado | 82,545 | 1.42% | 51 | City |
| Broomfield | Colorado | 80,154 | 1.24% | 53 | City |
| Missoula | Montana | 79,837 | 1.18% | 54 | City |
| Caldwell | Idaho | 79,746 | 4.07% | 55 | City |
| Commerce City | Colorado | 74,414 | 2.86% | 57 | City |
| Grand Junction | Colorado | 73,036 | 1.68% | 58 | City |
| Idaho Falls | Idaho | 72,700 | 1.27% | 60 | City |
| Eagle Mountain | Utah | 70,772 | 6.33% | 62 | City |
| Parker | Colorado | 67,604 | 2.45% | 64 | Town |
| Cheyenne | Wyoming | 66,580 | 0.11% | 65 | City |
| Saratoga Springs | Utah | 66,106 | 7.67% | 66 | City |
| Herriman | Utah | 64,814 | 2.42% | 67 | City |
| Millcreek | Utah | 64,057 | 0.2% | 68 | City |
| Great Falls | Montana | 60,117 | -0.15% | 69 | City |
| Bozeman | Montana | 59,872 | 1.8% | 70 | City |
| Pocatello | Idaho | 59,205 | 0.74% | 72 | City |
| Casper | Wyoming | 58,624 | -0.25% | 74 | City |
| Twin Falls | Idaho | 57,077 | 1.53% | 75 | City |
| Taylorsville | Utah | 56,848 | -1.11% | 76 | City |
| Logan | Utah | 56,477 | 1.62% | 77 | City |
| Murray | Utah | 53,982 | 1.29% | 78 | City |
| Draper | Utah | 50,437 | -0.42% | 81 | City |
| Spanish Fork | Utah | 50,052 | 2.49% | 82 | City |
For this list, the Mountain Time Zone Region is defined as the 7 states of Arizona, Colorado, Idaho, Montana, New Mexico, Utah and Wyoming.