I found 24 lines in http://download.geonames.org/export/zip/US.zip with "county/province" code but without "county/province" name, next to lines with the same code and including the name:
US 20020 Washington District of Columbia DC District of Columbia 001 38.86 -76.9742
US 20022 Washington District of Columbia DC 001 38.945 -77.0364