60021 is a postalcode and its consensus geometry is derived from uszcta.
{"mz:is_ceased":0,"geom:latitude":42.194857,"wof:name":"60021","counts:names_total":0,"wof:placetype":"postalcode","mz:is_current":1,"wof:hierarchy":[{"continent_id":102191575,"country_id":85633793,"county_id":102081661,"localadmin_id":404499077,"locality_id":85938395,"postalcode_id":554733159,"region_id":85688697}],"mz:is_deprecated":0,"lbl:latitude":42.194697,"geom:area":6.58E-4,"geom:longitude":-88.218158,"wof:id":554733159,"counts:concordances_total":1,"geom:type":"Polygon","wof:lastmodified":1611184211,"wof:belongsto":[102191575,85633793,102081661,404499077,85938395,85688697],"wof:concordances":{"gp:id":"12783951"},"wof:repo":"whosonfirst-data-postalcode-us","src:geom":"uszcta","wof:country":"US","counts:names_preferred":0,"gp:parent_id":"12588140","geom:area_square_m":6029219.979498,"wof:tags":[],"counts:names_variant":0,"wof:breaches":[],"edtf:inception":"uuuu","iso:country":"US","counts:names_languages":0,"geom:bbox":"-88.251036,42.184631,-88.189394,42.206136","wof:superseded_by":[],"wof:supersedes":[],"lbl:longitude":-88.217108,"wof:geomhash":"e37e0da6a208b215799eb261139e517b","wof:parent_id":85938395,"wof:placetype_names":["postalcode"],"mz:hierarchy_label":1,"wof:placetype_id":470996387,"edtf:cessation":"uuuu","mz:postal_locality":"Fox River Grove"}