Metropolitan area codes: 1968-1972
- 00001
- New York, NY
- 00002
- Los Angeles - Long Beach, CA
- 00003
- Chicago, IL
- 00004
- Philadelphia, PA
- 00005
- Detroit, MI
- 00006
- San Fransisco - Oakland, CA
- 00007
- Boston, MA
- 00008
- Pittsburg, PA
- 00009
- St. Louis, MO
- 00010
- Washington, D.C.-MD-VA
- 00011
- Cleveland, OH
- 00012
- Baltimore, MD
- 00013
- Newark, NJ
- 00014
- Minneapolis-St. Paul, MN
- 00015
- Buffalo, NY
- 00016
- Houston, TX
- 00017
- Milwaukee, WI
- 00018
- Patterson-Clifton-Passaic, NJ
- 00019
- Dallas, TX
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