ZIP Code Area 212XX
- ZIP Code Area 21201
- ZIP Code Area 21202
- ZIP Code Area 21204
- ZIP Code Area 21205
- ZIP Code Area 21206
- ZIP Code Area 21207
- ZIP Code Area 21208
- ZIP Code Area 21209
- ZIP Code Area 21210
- ZIP Code Area 21211
- ZIP Code Area 21212
- ZIP Code Area 21213
- ZIP Code Area 21214
- ZIP Code Area 21215
- ZIP Code Area 21216
- ZIP Code Area 21217
- ZIP Code Area 21218
- ZIP Code Area 21219
- ZIP Code Area 21220
- ZIP Code Area 21221
- ZIP Code Area 21222
- ZIP Code Area 21223
- ZIP Code Area 21224
- ZIP Code Area 21225
- ZIP Code Area 21226
- ZIP Code Area 21227
- ZIP Code Area 21228
- ZIP Code Area 21229
- ZIP Code Area 21230
- ZIP Code Area 21231
- ZIP Code Area 21234
- ZIP Code Area 21236
- ZIP Code Area 21237
- ZIP Code Area 21239
- ZIP Code Area 21240
- ZIP Code Area 21244
- ZIP Code Area 21250
- ZIP Code Area 21251
- ZIP Code Area 21252
- ZIP Code Area 21286