ZIP CodesZIP codes in Fall River County, South Dakota
Fall River County, South Dakota has 5 ZIP codes in this list, from 57735 to 57782. They cover 5 places, among them Edgemont, Hot Springs, Oelrichs and Oral.
| ZIP code | Place | Land area (sq mi) | Map point |
|---|---|---|---|
| 57735 | Edgemont | 905 | 43.287, -103.811 |
| 57747 | Hot Springs | 508 | 43.422, -103.477 |
| 57763 | Oelrichs | 374 | 43.155, -103.216 |
| 57766 | Oral | 143 | 43.388, -103.183 |
| 57782 | Smithwick | 51.0 | 43.301, -103.218 |
Where Fall River County is
The ZIP codes of Fall River County are found in the south-west of South Dakota. Its codes spread over about 18 miles from north to south and 32 miles from east to west. The two codes farthest apart are 57735 (Edgemont) and 57766 (Oral), about 32 miles from each other in a straight line. Measured between the middle points of their codes, the closest neighbours are Custer County (23 miles), Dawes County, Nebraska (45 miles), Oglala Lakota County (47 miles) and Sioux County, Nebraska (50 miles).
The first three digits
Every ZIP code of Fall River County starts with 577. The first three digits of a ZIP code name the mail sorting area it belongs to. The prefix 577 is shared with 9 other counties, such as Bennett County, Butte County and Custer County, and has 58 codes in all.
How much ground the codes cover
The Census Bureau draws an area for every code here. Together they come to about 1,980 square miles of land (5,128 sq km). The largest is 57735 (Edgemont) with 905 square miles, and the smallest is 57782 (Smithwick) with 51.0. The middle-sized code here covers 374 square miles; the middle value for all of South Dakota is 136. Large code areas usually go with open country, where one post office serves a wide district. These areas follow ZIP code delivery routes, so their total is not the official size of Fall River County; a code can reach across its border.
By number of ZIP codes, Fall River County ranks 31st among the 66 counties and county-level areas of South Dakota (equal counts share a rank), with 5 of the 385 codes in the state list.
Writing an address in Fall River County
The name of the county is not written in a United States address. The last line is the postal city, the letters SD and the ZIP code:
- Edgemont, SD 57735
- Hot Springs, SD 57747
- Oelrichs, SD 57763
Questions about Fall River County ZIP codes
What is the ZIP code for Edgemont, SD?
57735 is the ZIP code listed for Edgemont in Fall River County.
Do all ZIP codes in Fall River County start with the same digits?
Yes. All 5 start with 577.
Which ZIP code in Fall River County covers the most land?
57735 (Edgemont), at about 905 square miles in the Census Bureau's 2024 figures.
Using this list
- In an address, the ZIP code comes last, after the city and the two-letter state: Edgemont, SD 57735.
- Tap a ZIP code to open it in the look-up, with a copy button for the address line.
- A code can cross a county line, and one town can have several codes. The table shows the main place of each code.
- "No area" means the Census Bureau draws no area for that code. Such codes are usually for post office boxes or a single building.
Places and counties: GeoNames. Areas: U.S. Census Bureau, 2024 ZIP Code Tabulation Areas. Checked in November 2026. This site is not connected with the United States Postal Service; for mailing, confirm the address with USPS.