[UW-GIS-L] Zip + 4 Shapefile

[gthum at u.washington.edu]

Hello all,
Does anyone possess or know where to find a boundary shapefile for zipcodes
+ 4 (9-digit zipcodes) for the Puget Sound region (although King Co. alone
would suffice) ?  I've looked at WAGDA, Census, PSRC, King Co. and City of
Seattle, but have had no luck.  Any help would be appreciated.

Gabe Thum

Graduate Student
Civil and Environmental Engineering Department

Transportation Planner
University of Washington