ZIP Code 63121

63121 is one of Missouri's ZIP codes, delivering to addresses in Saint Louis, St. Louis County.

City: Saint Louis
County: St. Louis County
State: Missouri
Prefix: 631xx

Where this code sits

63121 is part of the 631xx range, the group of codes handled by one mail processing centre. Saint Louis is served by 68 ZIP codes in total.

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 63121 delivers to without sharing its boundary.

ZIP codes nearest 63121

The ZIP codes whose reference points sit closest to 63121.
ZIP code	Distance	Delivers to
ZIP code 63133	2.0 mi	Saint Louis, MO
ZIP code 63136	2.1 mi	Saint Louis, MO
ZIP code 63140	2.4 mi	Saint Louis, MO
ZIP code 63120	2.7 mi	Saint Louis, MO
ZIP code 63130	2.9 mi	Saint Louis, MO
ZIP code 63135	3.0 mi	Saint Louis, MO
ZIP code 63134	3.2 mi	Saint Louis, MO
ZIP code 63114	3.2 mi	Saint Louis, MO

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 63121, plotted from its record coordinates.

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

Scope ZIP code 63121. 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.