18351 is a postalcode and its consensus geometry is derived from uszcta.
{"mz:is_ceased":0,"geom:latitude":40.922831,"wof:name":"18351","counts:names_total":0,"wof:placetype":"postalcode","mz:is_current":1,"wof:hierarchy":[{"continent_id":102191575,"country_id":85633793,"county_id":102081395,"localadmin_id":404483653,"locality_id":101717867,"postalcode_id":554767703,"region_id":85688481}],"mz:is_deprecated":0,"lbl:latitude":40.92272,"geom:area":1.22E-4,"geom:longitude":-75.099502,"wof:id":554767703,"counts:concordances_total":1,"geom:type":"Polygon","wof:lastmodified":1611184258,"wof:belongsto":[102191575,85633793,102081395,404483653,101717867,85688481],"wof:concordances":{"gp:id":"12765156"},"wof:repo":"whosonfirst-data-postalcode-us","src:geom":"uszcta","wof:country":"US","counts:names_preferred":0,"gp:parent_id":"12589775","geom:area_square_m":1139424.785817,"wof:tags":[],"counts:names_variant":0,"wof:breaches":[],"edtf:inception":"uuuu","iso:country":"US","counts:names_languages":0,"geom:bbox":"-75.106916,40.915923,-75.087397,40.930257","wof:superseded_by":[],"wof:supersedes":[],"lbl:longitude":-75.099334,"wof:geomhash":"7becd7a47d6303b74f36c37a525adca8","wof:parent_id":101717867,"wof:placetype_names":["postalcode"],"mz:hierarchy_label":1,"wof:placetype_id":470996387,"edtf:cessation":"uuuu","mz:postal_locality":"Portland"}