ZIP Code 45040

45040 is one of Ohio's ZIP codes, delivering to addresses in Mason, Warren County.

City: Mason
County: Warren County
State: Ohio
Prefix: 450xx

Where this code sits

45040 is part of the 450xx range, the group of codes handled by one mail processing centre. It is the only ZIP code delivering to Mason.

Mason Ohio ZIP codes →

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 45040 delivers to without sharing its boundary.

ZIP codes nearest 45040

The ZIP codes whose reference points sit closest to 45040.
ZIP code	Distance	Delivers to
ZIP code 45034	3.9 mi	Kings Mills, OH
ZIP code 45039	4.0 mi	Maineville, OH
ZIP code 45069	4.5 mi	West Chester, OH
ZIP code 45249	4.7 mi	Cincinnati, OH
ZIP code 45071	4.9 mi	West Chester, OH
ZIP code 45065	6.1 mi	South Lebanon, OH
ZIP code 45242	6.5 mi	Cincinnati, OH
ZIP code 45140	7.0 mi	Loveland, OH

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 45040, plotted from its record coordinates.

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

Scope ZIP code 45040. 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.