Home/PostalMag/Post Office Photos/Seward, Alaska Post Office 99664 Post Office Photos Seward, Alaska Post Office 99664 PostalMag · Wednesday, August 07, 2019 The Seward, Alaska Post Office serves ZIP Code 99664. Photo by Jimmy Emerson, some rights reserved. Photo shared under the Creative Commons License. Seward Post Office 507 Madison St Seward, AK 99664