ZIP Code 57646

57646 is one of South Dakota's ZIP codes, delivering to addresses in Mound City, Campbell County.

City: Mound City
County: Campbell County
State: South Dakota
Prefix: 576xx

Where this code sits

57646 is part of the 576xx range, the group of codes handled by one mail processing centre. It is the only ZIP code delivering to Mound City.

Mound City South Dakota ZIP codes →

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 57646 delivers to without sharing its boundary.

605 Area code 605

ZIP codes nearest 57646

The ZIP codes whose reference points sit closest to 57646.
ZIP code	Distance	Delivers to
ZIP code 57632	12 mi	Herreid, SD
ZIP code 57472	14 mi	Selby, SD
ZIP code 57631	15 mi	Glenham, SD
ZIP code 57648	19 mi	Pollock, SD
ZIP code 57452	19 mi	Java, SD
ZIP code 57601	21 mi	Mobridge, SD
ZIP code 57658	24 mi	Wakpala, SD
ZIP code 57420	24 mi	Akaska, SD

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 57646, plotted from its record coordinates.

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

Scope ZIP code 57646. 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.