Oswego Kansas Area Code

One area code covers Oswego: 620.

Scope the codes matched to Oswego. Source geoinfo-dataset (full_dataset) ZIP→NPA (2018 snapshot) and LocalCallingGuide NPA list (2026-07 NPA list). Updated 16 July 2026. Overlay relationships come from the numbering-plan authority; the place match is computed.

Oswego has a single code, so there is nothing to divide — every local line carries 620.

Postal geography is organised separately from telephone geography, so Oswego’s 1 ZIP code do not map onto the codes above. They are listed in full, with the county each falls in, on the postal side of the site.

Oswego Kansas ZIP codes →

These are the closest places to Oswego whose area codes are not the same set. If you are near one of them, a local number may carry a code that is not on the list above.

Straight-line distance between place reference points, not driving distance.