ZIP Code 99635 — Nikiski, AK
99635 is a standard (street delivery) ZIP code serving Nikiski, Alaska, in Kenai Peninsula 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 99635 at a glance
| ZIP code | 99635 |
|---|---|
| Primary city | Nikiski |
| State | Alaska (AK) |
| County | Kenai Peninsula FIPS 02122 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Anchorage |
| Population | 100 |
| Coordinates | 60.806200, -152.677340 |
How ZIP+4 works in 99635
The four digits after the hyphen encode a delivery segment inside 99635. 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 99635 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.
Questions about 99635
What is the ZIP+4 code for 99635?
99635 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 99635, you need to look up a specific street address to get them.
What city is 99635?
99635 is assigned to Nikiski, Alaska, in Kenai Peninsula 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.
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