59901 is a postalcode and its consensus geometry is derived from uszcta.
{"mz:is_ceased":0,"geom:latitude":48.228155,"wof:name":"59901","counts:names_total":0,"wof:placetype":"postalcode","mz:is_current":1,"wof:hierarchy":[{"continent_id":102191575,"country_id":85633793,"county_id":102085177,"postalcode_id":554733091,"region_id":85688617}],"mz:is_deprecated":0,"lbl:latitude":48.229649,"geom:area":0.145715,"geom:longitude":-114.382217,"wof:id":554733091,"counts:concordances_total":1,"geom:type":"Polygon","wof:lastmodified":1611184220,"wof:belongsto":[102191575,85633793,102085177,85688617],"wof:concordances":{"gp:id":"12783901"},"wof:repo":"whosonfirst-data-postalcode-us","src:geom":"uszcta","wof:country":"US","counts:names_preferred":0,"geom:area_square_m":1.20029726950117E9,"wof:tags":[],"counts:names_variant":0,"wof:breaches":[],"edtf:inception":"uuuu","iso:country":"US","counts:names_languages":0,"geom:bbox":"-114.776855,48.035656,-113.920108,48.424367","wof:superseded_by":[],"wof:supersedes":[],"lbl:longitude":-114.385053,"wof:geomhash":"44d29a47299e645340777977cc6164ac","wof:parent_id":102085177,"wof:placetype_names":["postalcode"],"mz:hierarchy_label":1,"wof:placetype_id":470996387,"edtf:cessation":"uuuu","mz:postal_locality":"Kalispell"}