The map above shows Montana and New Mexico side by side at exactly the same scale, using equal-area projections, so their true relative sizes are preserved.
Montana vs New Mexico Geography
Land area: Montana has a land area of 145,550 square miles (376,973 km²), while New Mexico has 121,313 square miles (314,198 km²). Montana's land area is 1.2 times (20%) larger than New Mexico's.
Total area: Montana: 147,043 square miles (380,840 km²) vs New Mexico: 121,593 square miles (314,925 km²), including inland and coastal water. Montana's total area is 1.2 times (21%) larger than New Mexico's.
Length: Montana is 319 miles (514 km) long from north to south; New Mexico is 395 miles (635 km). New Mexico's north-south length is 1.2 times (24%) longer than Montana's.
Width: Montana spans 607 miles (976 km) east to west; New Mexico spans 498 miles (801 km). Montana's east-west width is 1.2 times (22%) wider than New Mexico's.
Highest point: Montana's highest point is Granite Peak at 12,767 feet (3,891 m); New Mexico's is Wheeler Peak at 13,150 feet (4,008 m). Wheeler Peak is 383 feet higher than Granite Peak.
Lowest point: Montana's lowest point is Kootenai River at 1,805 feet; New Mexico's is Red Bluff Reservoir at 2,842 feet. Montana's lowest point is 1,037 feet lower.
Montana vs New Mexico Population and History
Population: Montana has a population of 1,137,233 (2024), while New Mexico has 2,130,256 (2024). New Mexico's population is 1.9 times (87%) larger than Montana's.
Population density: Montana: 7.8 people per square mile vs New Mexico: 17.6. New Mexico's population density is 2.3 times (126%) higher than Montana's.
Biggest city: Montana's biggest city is Billings with 121,483 people; New Mexico's is Albuquerque with 560,326. Albuquerque's population is 4.6 times (361%) larger than Billings'.
Largest metro area: Montana's largest metropolitan area is Billings, MT metro area (192,531 people) vs New Mexico's Albuquerque, NM metro area (926,303). Albuquerque, NM metro area's population is 4.8 times (381%) larger than Billings, MT metro area's.
History: Montana: Admitted to the Union on November 8, 1889, as the 41st state. New Mexico: Admitted to the Union on January 6, 1912, as the 47th state. In its current form, Montana is the older of the two by 23 years.
Montana vs New Mexico Economy
GDP: Montana's GDP is $78.4 billion (2024) vs New Mexico's $147.1 billion. New Mexico's economic output is 1.9 times (88%) larger than Montana's.
GDP per capita: Montana: $68,975 per person vs New Mexico: $69,046. Montana and New Mexico have about the same GDP per capita.
Average income: Montana: $69,240 vs New Mexico: $58,249 average income per person (per capita personal income). Montana's average income is 1.2 times (19%) higher than New Mexico's.
Montana vs New Mexico Counties
Number of counties: Montana has 56 counties, while New Mexico has 33. Montana's county count is 1.7 times (70%) higher than New Mexico's.
Biggest county by area: Montana's largest county is Beaverhead County at 5,543 square miles; New Mexico's is Catron County at 6,924 square miles. Catron County's land area is 1.2 times (25%) larger than Beaverhead County's.
Smallest county by area: Montana: Silver Bow County (718 sq mi) vs New Mexico: Los Alamos County (109 sq mi). Silver Bow County's land area is 6.6 times (558%) larger than Los Alamos County's.
Most populous county: Montana: Yellowstone County (171,583 people) vs New Mexico: Bernalillo County (671,747 people). Bernalillo County's population is 3.9 times (291%) larger than Yellowstone County's.
Least populous county: Montana: Petroleum County (525 people) vs New Mexico: Harding County (635 people). Harding County's population is 1.2 times (21%) larger than Petroleum County's.
Richest county: Montana: Gallatin County ($94,573 per capita income) vs New Mexico: Los Alamos County ($98,378). Gallatin County and Los Alamos County have about the same income.
Poorest county: Montana: Blaine County ($37,554 per capita income) vs New Mexico: Cibola County ($36,397). Blaine County and Cibola County have about the same income.
Montana vs New Mexico Taxes
State income tax: Montana has a top income tax rate of 5.65%, while New Mexico has a top income tax rate of 5.9%. New Mexico's top rate is 0.25 percentage points higher.
Property tax: Montana: 0.69% effective rate vs New Mexico: 0.63% of home value per year. Montana's rate is 0.06 percentage points higher.
Sales tax: Montana: 0% combined state and average local rate vs New Mexico: 7.68%. New Mexico's combined rate is 7.68 percentage points higher.
Official Websites
Montana official website · New Mexico official website
More Size Comparisons
All Montana size comparisons · All New Mexico size comparisons
Area, elevation and boundary figures come from official national statistics and US Census Bureau and Natural Earth boundary data; US state population, economic, county and tax figures come from the US Census Bureau, the Bureau of Economic Analysis and the Tax Foundation. Figures are rounded and for general reference.