ZIP Code 59421

59421 is one of Montana's ZIP codes, delivering to addresses in Cascade, Cascade County.

City: Cascade
County: Cascade County
State: Montana
Prefix: 594xx

Where this code sits

59421 is part of the 594xx range, the group of codes handled by one mail processing centre. It is the only ZIP code delivering to Cascade.

Cascade Montana ZIP codes →

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 59421 delivers to without sharing its boundary.

406 Area code 406

ZIP codes nearest 59421

The ZIP codes whose reference points sit closest to 59421.
ZIP code	Distance	Delivers to
ZIP code 59485	7.4 mi	Ulm, MT
ZIP code 59483	13 mi	Sun River, MT
ZIP code 59443	15 mi	Fort Shaw, MT
ZIP code 59477	16 mi	Simms, MT
ZIP code 59487	20 mi	Vaughn, MT
ZIP code 59404	23 mi	Great Falls, MT
ZIP code 59402	24 mi	Malmstrom Afb, MT
ZIP code 59403	24 mi	Great Falls, MT

Straight-line distance between place reference points, not driving distance. Where a place has no Census Gazetteer point, its postal centroid is used instead.

Each point is the reference point for 59421, plotted from its record coordinates.

Reference points and footprint
Not an official NANPA boundary
Not a USPS delivery area

Scope ZIP code 59421. Source GeoNames US postal codes (2026-07 postal dump) and Census 2024 county Gazetteer (2024 Gazetteer). Updated 15 July 2026. A ZIP code is a set of delivery routes, not an area; the point shown is a record coordinate, not a centre.