States & postal codes

Postal codes

The first two digits of a postal code tell you the state. Mexico City uses 01 to 16, and the states go from 20 to 99 in alphabetical order.

Try it

Postal code42800Valid

State: Hidalgo
CURP code: HG
INEGI code: 13
ISO code: MX-HID

import { stateFromPostalCode, normalizePostalCode } from "mexico-utils";

stateFromPostalCode("42800")?.name; // "Hidalgo"
stateFromPostalCode(1000)?.name;    // "Ciudad de México", the leading zero comes back
stateFromPostalCode("17000");       // null, nobody uses 17

normalizePostalCode(1000);          // "01000"

You get the state, not the municipality. That needs SEPOMEX's full catalog, which is several megabytes.

States

STATES has the 32 federal entities in INEGI order, each with every code you're likely to need:

import { STATES, findState } from "mexico-utils";

findState("hidalgo");
// { name: "Hidalgo", curp: "HG", inegi: "13", iso: "MX-HID", postalPrefixes: [42, 43] }

findState("CDMX");       // Ciudad de México
findState("Nuevo Leon"); // accents and case don't matter
findState("MX-YUC");     // ISO code
findState(15);           // INEGI code, Estado de México

findState also understands "Edomex", "DF" and the long official names like "Veracruz de Ignacio de la Llave". The full table is on the states page.