Mount St. Helens is a volcano, not a city or town, so it doesn't have a zip code.

The closest towns to Mount St. Helens are:

* Castle Rock, WA: 98611

* Toutle, WA: 98650

* Longview, WA: 98632

* Woodland, WA: 98674

To be more precise, the Mount St. Helens National Volcanic Monument encompasses portions of different counties and zip codes.