Census division 8
The Mountain division
The Mountain division has 8 states with 26,167,683 residents in the Census Vintage 2024 estimates, 7.7% of the US total, on 856,346 square miles of land. It ranks 6th of 9 divisions by population and 2nd by land area.
- Residents 2024
- 26,167,683
- 7.7% of the US
- Land area
- 856,346 sq mi
- Density
- 30.6 / sq mi
- Member states
- 8
- 281 counties
Member states shaded by density; others hatched. Pins mark capitals.
Mountain population and land
The Mountain division has 8 states with 26,167,683 residents in the Census Vintage 2024 estimates, 7.7% of the US total, on 856,346 square miles of land. It ranks 6th of 9 divisions by population and 2nd by land area. It averages 30.6 people per square mile, 3.1 times sparser than the national figure of 96.3, and ranks 9th of 9 by density.
Arizona is the most populous member with 7,582,384 residents, 29% of the division, while Montana is the largest by land at 145,550 square miles. Wyoming is the least populous, with 587,618.
States in the Mountain division
The Census Bureau groups the states into 4 regions and 9 divisions for statistics. Mountain is division 8, part of the West region. Totals below are sums of Vintage 2024 county estimates and 2024 Gazetteer land area.
| State | Residents | Share | Land sq mi | Per sq mi | Counties |
|---|---|---|---|---|---|
| Arizona | 7,582,384 | 29.0% | 113,655 | 66.7 | 15 |
| Colorado | 5,957,493 | 22.8% | 103,637 | 57.5 | 64 |
| Utah | 3,503,613 | 13.4% | 82,596 | 42.4 | 29 |
| Nevada | 3,267,467 | 12.5% | 109,860 | 29.7 | 17 |
| New Mexico | 2,130,256 | 8.1% | 121,313 | 17.6 | 33 |
| Idaho | 2,001,619 | 7.6% | 82,645 | 24.2 | 44 |
| Montana | 1,137,233 | 4.3% | 145,550 | 7.8 | 56 |
| Wyoming | 587,618 | 2.2% | 97,089 | 6.1 | 23 |
Counties in the Mountain division
Its 281 county-equivalents have a median of 14,518 residents, below the national median county of 26,122. The most populous is Maricopa County, AZ, with 4,673,096; the largest by land is Coconino County, AZ, at 18,616 square miles.
The median county household income here is $65,695 in SAIPE 2023, 5% above the national median county, $62,851. It ranges from $37,108 in Mineral County, CO to $146,208 in Los Alamos County, NM.
- 01Maricopa County, AZ4,673,096
- 02Clark County, NV2,398,871
- 03Salt Lake County, UT1,216,274
- 04Pima County, AZ1,080,149
- 05El Paso County, CO752,772
- 06Utah County, UT747,234
- 07Denver County, CO729,019
- 08Bernalillo County, NM671,747
- 09Arapahoe County, CO666,918
- 10Jefferson County, CO578,533
Distances and center
The two member capitals farthest apart are Phoenix and Helena, 908 miles in a straight line. Weighting every county's internal point by population puts the division's center of population near 37.89° N, 110.65° W. The method is explained in the center of population guide.
Bordering states compared
15 pairs of member states share a border. Each comparison puts population, land, counties and capitals side by side.
Questions people ask
What states are in the Mountain division?
Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, Wyoming, per the Census Bureau's regions and divisions.
What is the population of the Mountain division?
26,167,683 in the Census Vintage 2024 estimates, 7.7% of the US.
What is the largest state in the Mountain division?
Montana by land (145,550 square miles) and Arizona by population (7,582,384).
What is the most populous county in the Mountain division?
Maricopa County, AZ, with 4,673,096 residents.
Which Census region is the Mountain division in?
The West region, which also includes the Pacific division.
Sources and data as of
Data as of: Census Vintage 2024 population estimates, 2024 Gazetteer land area and internal points, SAIPE 2023 median household income.
- 01Census Bureau regions and divisions of the United States (last verified 2026-09-30)
- 02Census Vintage 2024 county population estimates
- 03Census 2024 Gazetteer, counties
- 04Census SAIPE 2023 state and county estimates
How every number is computed: methodology. Spotted a wrong figure? Report an error.