ZIP Code 19966 — Millsboro, DE
19966 is a standard (street delivery) ZIP code serving Millsboro, Delaware, in Sussex 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 19966 at a glance
| ZIP code | 19966 |
|---|---|
| Primary city | Millsboro |
| State | Delaware (DE) |
| County | Sussex FIPS 10005 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 35,884 |
| Coordinates | 38.581180, -75.282740 |
How ZIP+4 works in 19966
The four digits after the hyphen encode a delivery segment inside 19966. 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 19966 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 19966.
| ZIP | City | Distance |
|---|---|---|
| 19939 | Dagsboro, DE | 4.5 mi |
| 19945 | Frankford, DE | 6.1 mi |
| 19951 | Harbeson, DE | 7.5 mi |
| 19947 | Georgetown, DE | 9 mi |
| 19967 | Millville, DE | 9.2 mi |
| 19975 | Selbyville, DE | 9.7 mi |
| 19970 | Ocean View, DE | 10.1 mi |
| 21872 | Whaleyville, MD | 11.4 mi |
| 19930 | Bethany Beach, DE | 11.5 mi |
| 19958 | Lewes, DE | 11.9 mi |
| 21813 | Bishopville, MD | 12.2 mi |
| 19971 | Rehoboth Beach, DE | 12.4 mi |
Questions about 19966
What is the ZIP+4 code for 19966?
19966 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 19966, you need to look up a specific street address to get them.
What city is 19966?
19966 is assigned to Millsboro, Delaware, in Sussex 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.