PlainZIP

Changelog

First published February 22, 2026 · revised October 9, 2026

October 2026: version 3

Every ZIP code page rebuilt around the lookup: town, county share, map with neighboring ZIP codes, the ZIP's rank inside its town and county.
PO Box, single-organization and military ZIP codes added to their towns' pages and the ZIP code types guide.
New data: ACS 2015-2019 for change over time, the 2020 and 2010 Census counts, FHFA's house price index through 2025, ZIP Business Patterns 2018, IRS income per tax return.
City, county and prefix pages list every ZIP code on a map; a town with one ZIP code now lives on that ZIP's page.
Data corrections listed on the corrections page.

PlainZIP launched.