A Split-State Map: 45.1% of Montana Lives Near Helena, 54.9% Beyond

By SimpleMapLab·Published 13 May 2026·Rank #38 of 50 states·↑ All 50 states

45.1% of Montana’s population — about 504 K of 1.12 M residents — lives within 100 miles of Helena. The other 54.9% — including Billings — sits beyond the circle.

A 100-mile geodesic radius around the Helena, MT state capitol overlaid on Montana. 45.1% of Montana's population lives inside the dashed ring.

45.1%

of Montana’s population within 100 miles of Helena

504 K

residents inside the radius (of 1.12 M statewide)

34 mi

from Helena to Montana’s population centroid

#38

of 50 states ranked by capital-to-population centrality

Open this radius in the map → /tools/map-radius-tool · Helena, MT · 100 mi
The link opens the SimpleMapLab Map Radius Tool with the 100-mile circle already drawn around the Helena capitol. Change the radius to 50, 250, or any value to compare different framings.

Why this happened

Montana is a "split" state by this measure: roughly half its residents live within an hour and a half of the capital, and roughly half live beyond. Helena's 100-mile reach captures Missoula (~94K) and the surrounding counties, but stops well short of Billings, which sits 188 miles away. The capital-to-population-centroid distance is 34 miles — a clear signal that political and demographic weight no longer share a single point on the map.

The biggest cities inside the 100-mile radius

The top 5 most-populous places (by aggregated ZIP code population) sitting inside the 100-mile circle around Helena. Cities are listed by total population captured by ZIP centroids in the dataset.

#	City	Population in radius
1	Missoula	93,936
2	Bozeman	84,228
3	Great Falls	75,427
4	Helena	63,145
5	Butte	34,732

The largest city outside the radius

Montana’s most-populous city outside the 100-mile circle is Billings, sitting 188 miles from Helena. The aggregated population of Billings’s ZIP codes alone — 147,124 residents — illustrates the gap between Montana’s political seat and its population centre.

How Montana compares

The states ranked closest to Montana on this metric. Click any to compare the radius breakdown directly.

#37 Mississippi

Jackson · 49.4% pop. captured

#39 Tennessee

Nashville · 44.2% pop. captured

#36 Iowa

Des Moines · 49.8% pop. captured

#40 Missouri

Jefferson City · 43.8% pop. captured

#35 Arkansas

Little Rock · 51.4% pop. captured

Draw it yourself

Open the 100-mile circle around Helena →

The Map Radius Tool lets you change the radius (try 50 mi for an urban-suburban question or 250 mi for “a day’s drive”), drag the centre to compare Helena’s reach with that of Missoula, or add a second circle for a side-by-side comparison.

Methodology (brief)

We took the lat/lng of the Montana state capitol building (46.5891°, -112.0391°) and drew a 100-mile geodesic radius. For every ZIP code in Montana, we tested whether the ZIP centroid falls inside; if so, its population counts. We then divide by Montana’s total population to produce the percentage. The full methodology for all 50 states is on the hub page.

Suggested citation: SimpleMapLab (2026). 100 Miles Around Helena: How Much of Montana Is Inside? Part of the State Capital Radius study. Retrieved from https://www.simplemaplab.com/studies/state-capital-radius/montana. Licensed under CC-BY 4.0.