21222 is a postalcode and its consensus geometry is derived from uszcta.
{"mz:is_ceased":0,"geom:latitude":39.265478,"wof:name":"21222","counts:names_total":0,"wof:placetype":"postalcode","mz:is_current":1,"wof:hierarchy":[{"continent_id":102191575,"country_id":85633793,"county_id":102082193,"locality_id":85950181,"postalcode_id":554780515,"region_id":85688501}],"mz:is_deprecated":0,"lbl:latitude":39.26484,"mz:postal_locality_alt":["Baltimore"],"geom:area":0.003559,"geom:longitude":-76.493453,"wof:id":554780515,"counts:concordances_total":1,"geom:type":"Polygon","wof:lastmodified":1611185195,"wof:belongsto":[102191575,85633793,102082193,85950181,85688501],"wof:concordances":{"gp:id":"12766515"},"wof:repo":"whosonfirst-data-postalcode-us","src:geom":"uszcta","wof:country":"US","counts:names_preferred":0,"gp:parent_id":"12588678","geom:area_square_m":3.4068854230669E7,"wof:tags":[],"counts:names_variant":0,"wof:breaches":[],"edtf:inception":"uuuu","iso:country":"US","counts:names_languages":0,"geom:bbox":"-76.540876,39.222702,-76.443482,39.292305","wof:superseded_by":[],"wof:supersedes":[],"lbl:longitude":-76.492565,"wof:geomhash":"a91d47333da83d2157908d88308ac6c9","wof:parent_id":85950181,"wof:placetype_names":["postalcode"],"mz:hierarchy_label":1,"wof:placetype_id":470996387,"edtf:cessation":"uuuu","mz:postal_locality":"Dundalk"}