ZIP Code 18631

18631 is one of Pennsylvania's ZIP codes, delivering to addresses in Mifflinville, Columbia County.

City: Mifflinville
County: Columbia County
State: Pennsylvania
Prefix: 186xx

Where this code sits

18631 is part of the 186xx range, the group of codes handled by one mail processing centre. It is the only ZIP code delivering to Mifflinville.

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 18631 delivers to without sharing its boundary.

ZIP codes nearest 18631

The ZIP codes whose reference points sit closest to 18631.
ZIP code	Distance	Delivers to
ZIP code 18603	4.1 mi	Berwick, PA
ZIP code 18635	5.8 mi	Nescopeck, PA
ZIP code 17859	6.1 mi	Orangeville, PA
ZIP code 17815	6.9 mi	Bloomsburg, PA
ZIP code 18601	7.3 mi	Beach Haven, PA
ZIP code 18246	7.9 mi	Rock Glen, PA
ZIP code 17878	8.8 mi	Stillwater, PA
ZIP code 18241	9.6 mi	Nuremberg, PA

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 18631, plotted from its record coordinates.

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

Scope ZIP code 18631. 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.