Every ZIP code in the United States, with weather, radar, trivia and the numbers behind it. Five digits since 1963!

ZIP stands for Zone Improvement Plan. The codes went live on July 1, 1963.The lowest ZIP code is 00501 — the IRS in Holtsville, New York.The highest ZIP code is 99950, in Ketchikan, Alaska.Type 07734 into a calculator and turn it upside down: hELLO. It is Keansburg, New Jersey.12345 belongs to one company: General Electric in Schenectady, New York.The first digit is a region: 0 is New England and New Jersey, 9 is the West Coast, Alaska and Hawaii.Mr. ZIP, the cartoon mailman, was the mascot that sold the idea to America.ZIP+4 arrived in 1983 and can narrow a ZIP down to one side of one block.A ZIP code is a mail route, not a place: plenty of them cross county and even state lines.Play ZIP Hunt: guess the secret ZIP code of the day in six tries.
zipcodes.pro — RANKINGS/MT/HIGHEST-DENSITY

Most Densely Populated ZIP Codes in Montana

What this measures. People per square mile of land area. Source: Census American Community Survey and Gazetteer, data release 2026-10-12.

# ZIP City County People per sq mi
1 59625 Helena Lewis and Clark 7,286
2 59812 Missoula Missoula 5,493
3 59401 Great Falls Cascade 4,478
4 59801 Missoula Missoula 4,009
5 59102 Billings Yellowstone 3,190
6 59855 Pablo Lake 1,187
7 59841 Pinesdale Ravalli 639
8 59231 Saint Marie Valley 551
9 59414 Black Eagle Cascade 448
10 59802 Missoula Missoula 438
11 59851 Milltown Missoula 411
12 59105 Billings Yellowstone 370
13 59919 Hungry Horse Flathead 299
14 59718 Bozeman Gallatin 271
15 59601 Helena Lewis and Clark 244
16 59106 Billings Yellowstone 191
17 59803 Missoula Missoula 190
18 59808 Missoula Missoula 150
19 59901 Kalispell Flathead 135
20 59715 Bozeman Gallatin 134
21 59635 East Helena Lewis and Clark 104
22 59404 Great Falls Cascade 87
23 59912 Columbia Falls Flathead 83
24 59101 Billings Yellowstone 72
25 59044 Laurel Yellowstone 70
26 59405 Great Falls Cascade 70
27 59932 Somers Flathead 68
28 59701 Butte Silver Bow 67
29 59804 Missoula Missoula 64
30 59922 Lakeside Flathead 61
31 59602 Helena Lewis and Clark 59
32 59714 Belgrade Gallatin 58
33 59870 Stevensville Ravalli 49
34 59937 Whitefish Flathead 49
35 59217 Crane Richland 47
36 59013 Boyd Carbon 46
37 59860 Polson Lake 46
38 59833 Florence Ravalli 41
39 59323 Colstrip Rosebud 39
40 59864 Ronan Lake 39
41 59834 Frenchtown Missoula 37
42 59910 Big Arm Lake 36
43 59828 Corvallis Ravalli 35
44 59741 Manhattan Gallatin 35
45 59063 Park City Stillwater 34
46 59914 Dayton Lake 31
47 59756 Warm Springs Deer Lodge 30
48 59840 Hamilton Ravalli 29
49 59875 Victor Ravalli 29
50 59487 Vaughn Cascade 28

Showing the top 50 of 369 ZIP codes in Montana that have this figure . 59625 ranks 1st at 7,286, against 28 in 50th place.

Other rankings for Montana

Cite this page

zipcodes.pro. “Most Densely Populated ZIP Codes in Montana.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/rankings/mt/highest-density

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