ZIP Code 77470 — Rock Island, TX
77470 is a standard (street delivery) ZIP code serving Rock Island, Texas, in Colorado County. To mail something here you only need these five digits — but the four-digit extension narrows delivery to a single point, and it is what USPS bulk postage discounts are priced on.
ZIP code 77470 at a glance
| ZIP code | 77470 |
|---|---|
| Primary city | Rock Island |
| State | Texas (TX) |
| County | Colorado FIPS 48089 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 414 |
| Coordinates | 29.527750, -96.553050 |
How ZIP+4 works in 77470
The four digits after the hyphen encode a delivery segment inside 77470. In practice one segment usually means:
- One side of one block — odd numbers on a street between two cross streets
- A single large building, or one floor of it
- A group of PO boxes, sometimes a single box
- A single business that receives enough mail to warrant its own code
That is why 77470 has no single ZIP+4: two neighbors across the street from each other usually have different ones. Enter a street address above and we will return the exact nine-digit code along with the standardized USPS address format.
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 77470.
| ZIP | City | Distance |
|---|---|---|
| 77412 | Altair, TX | 6.2 mi |
| 77475 | Sheridan, TX | 6.6 mi |
| 77442 | Garwood, TX | 7.1 mi |
| 78943 | Glidden, TX | 12 mi |
| 78934 | Columbus, TX | 12.1 mi |
| 78935 | Alleyton, TX | 13.3 mi |
| 77460 | Nada, TX | 13.5 mi |
| 77434 | Eagle Lake, TX | 14 mi |
| 78962 | Weimar, TX | 14.8 mi |
| 77986 | Sublime, TX | 15 mi |
| 78951 | Oakland, TX | 18.1 mi |
| 77454 | Lissie, TX | 19.4 mi |
Questions about 77470
What is the ZIP+4 code for 77470?
77470 is the five-digit ZIP code. The ZIP+4 adds four more digits that identify a specific delivery point — usually one side of a city block, a single building, or a group of PO boxes. Because those four digits change from address to address within 77470, you need to look up a specific street address to get them.
What city is 77470?
77470 is assigned to Rock Island, Texas, in Colorado County.
Do I need to use the ZIP+4?
It is optional for ordinary mail, but it speeds up sorting and it is required for most USPS bulk-mail postage discounts. Many address-verification and e-commerce systems also use ZIP+4 to confirm a delivery point exists.
Need thousands of these?
Upload a CSV and get ZIP+4, county, carrier route, and delivery-point data appended to every row — or call the API directly.