A PO BOX szám lehet kevesebb, mint négyjegyű. A postafiókok esetében az általános szabály az, hogy minden doboznak megvan a maga ZIP + 4 kódja.
Az utolsó négy számjegy gyakran a következők egyike:
1. Nulla plusz a doboz számának utolsó három számjegye (eg. PO BOX 1001, Los Angeles CA 90001-0001).
2. A doboz utolsó négy számjegye (eg. PO BOX 9991, Twin Peaks CA 92391-9991).
3. Ha a doboz száma kevesebb, mint négy számjegy, akkor a nulla elejéhez elegendő nullát kell készíteni egy négyjegyű szám előállításához(eg. PO BOX 1, Shreveport LA 71161-0001).
Nincs azonban egységes szabály, az irányítószám plusz négy csak referenciaként szolgál, a ZIP + 4 kódot egyedileg kell megkeresni az egyes mezőkhöz az USPS hivatalos webhelyén.
PO BOX 150, BISHOPVILLE, SC 29010-0150
PO BOX 151, BISHOPVILLE, SC 29010-0151
PO BOX 152, BISHOPVILLE, SC 29010-0152
PO BOX 153, BISHOPVILLE, SC 29010-0153
PO BOX 154, BISHOPVILLE, SC 29010-0154
PO BOX 155, BISHOPVILLE, SC 29010-0155
PO BOX 156, BISHOPVILLE, SC 29010-0156
PO BOX 157, BISHOPVILLE, SC 29010-0157
PO BOX 158, BISHOPVILLE, SC 29010-0158
PO BOX 159, BISHOPVILLE, SC 29010-0159
PO BOX 160, BISHOPVILLE, SC 29010-0160
PO BOX 161, BISHOPVILLE, SC 29010-0161
PO BOX 162, BISHOPVILLE, SC 29010-0162
PO BOX 163, BISHOPVILLE, SC 29010-0163
PO BOX 164, BISHOPVILLE, SC 29010-0164
PO BOX 165, BISHOPVILLE, SC 29010-0165
PO BOX 166, BISHOPVILLE, SC 29010-0166
PO BOX 167, BISHOPVILLE, SC 29010-0167
PO BOX 168, BISHOPVILLE, SC 29010-0168
PO BOX 169, BISHOPVILLE, SC 29010-0169
PO BOX 170, BISHOPVILLE, SC 29010-0170
PO BOX 171, BISHOPVILLE, SC 29010-0171
PO BOX 172, BISHOPVILLE, SC 29010-0172
PO BOX 173, BISHOPVILLE, SC 29010-0173
PO BOX 174, BISHOPVILLE, SC 29010-0174
PO BOX 175, BISHOPVILLE, SC 29010-0175
PO BOX 176, BISHOPVILLE, SC 29010-0176
PO BOX 177, BISHOPVILLE, SC 29010-0177
PO BOX 178, BISHOPVILLE, SC 29010-0178
PO BOX 179, BISHOPVILLE, SC 29010-0179
PO BOX 180, BISHOPVILLE, SC 29010-0180
PO BOX 181, BISHOPVILLE, SC 29010-0181
PO BOX 182, BISHOPVILLE, SC 29010-0182
PO BOX 183, BISHOPVILLE, SC 29010-0183
PO BOX 184, BISHOPVILLE, SC 29010-0184
PO BOX 185, BISHOPVILLE, SC 29010-0185
PO BOX 186, BISHOPVILLE, SC 29010-0186
PO BOX 187, BISHOPVILLE, SC 29010-0187
PO BOX 188, BISHOPVILLE, SC 29010-0188
PO BOX 189, BISHOPVILLE, SC 29010-0189
PO BOX 190, BISHOPVILLE, SC 29010-0190
PO BOX 191, BISHOPVILLE, SC 29010-0191
PO BOX 192, BISHOPVILLE, SC 29010-0192
PO BOX 193, BISHOPVILLE, SC 29010-0193
PO BOX 194, BISHOPVILLE, SC 29010-0194
PO BOX 195, BISHOPVILLE, SC 29010-0195
PO BOX 196, BISHOPVILLE, SC 29010-0196
PO BOX 197, BISHOPVILLE, SC 29010-0197
PO BOX 198, BISHOPVILLE, SC 29010-0198
PO BOX 199, BISHOPVILLE, SC 29010-0199
PO BOX 200, BISHOPVILLE, SC 29010-0200
PO BOX 201, BISHOPVILLE, SC 29010-0201
PO BOX 202, BISHOPVILLE, SC 29010-0202
PO BOX 203, BISHOPVILLE, SC 29010-0203
PO BOX 204, BISHOPVILLE, SC 29010-0204
PO BOX 205, BISHOPVILLE, SC 29010-0205
PO BOX 206, BISHOPVILLE, SC 29010-0206
PO BOX 207, BISHOPVILLE, SC 29010-0207
PO BOX 208, BISHOPVILLE, SC 29010-0208
PO BOX 209, BISHOPVILLE, SC 29010-0209
PO BOX 210, BISHOPVILLE, SC 29010-0210
PO BOX 211, BISHOPVILLE, SC 29010-0211
PO BOX 212, BISHOPVILLE, SC 29010-0212
PO BOX 213, BISHOPVILLE, SC 29010-0213
PO BOX 214, BISHOPVILLE, SC 29010-0214
PO BOX 215, BISHOPVILLE, SC 29010-0215
PO BOX 216, BISHOPVILLE, SC 29010-0216
PO BOX 217, BISHOPVILLE, SC 29010-0217
PO BOX 218, BISHOPVILLE, SC 29010-0218
PO BOX 219, BISHOPVILLE, SC 29010-0219
PO BOX 220, BISHOPVILLE, SC 29010-0220
PO BOX 221, BISHOPVILLE, SC 29010-0221
PO BOX 222, BISHOPVILLE, SC 29010-0222
PO BOX 223, BISHOPVILLE, SC 29010-0223
PO BOX 224, BISHOPVILLE, SC 29010-0224
PO BOX 225, BISHOPVILLE, SC 29010-0225
PO BOX 226, BISHOPVILLE, SC 29010-0226
PO BOX 227, BISHOPVILLE, SC 29010-0227
PO BOX 228, BISHOPVILLE, SC 29010-0228
PO BOX 229, BISHOPVILLE, SC 29010-0229
PO BOX 230, BISHOPVILLE, SC 29010-0230
PO BOX 231, BISHOPVILLE, SC 29010-0231
PO BOX 232, BISHOPVILLE, SC 29010-0232
PO BOX 233, BISHOPVILLE, SC 29010-0233
PO BOX 234, BISHOPVILLE, SC 29010-0234
PO BOX 235, BISHOPVILLE, SC 29010-0235
PO BOX 236, BISHOPVILLE, SC 29010-0236
PO BOX 237, BISHOPVILLE, SC 29010-0237
PO BOX 238, BISHOPVILLE, SC 29010-0238
PO BOX 239, BISHOPVILLE, SC 29010-0239
PO BOX 240, BISHOPVILLE, SC 29010-0240
PO BOX 241, BISHOPVILLE, SC 29010-0241
PO BOX 242, BISHOPVILLE, SC 29010-0242
PO BOX 243, BISHOPVILLE, SC 29010-0243
PO BOX 244, BISHOPVILLE, SC 29010-0244
PO BOX 245, BISHOPVILLE, SC 29010-0245
PO BOX 246, BISHOPVILLE, SC 29010-0246
PO BOX 247, BISHOPVILLE, SC 29010-0247
PO BOX 248, BISHOPVILLE, SC 29010-0248
PO BOX 249, BISHOPVILLE, SC 29010-0249
PO BOX 250, BISHOPVILLE, SC 29010-0250
PO BOX 251, BISHOPVILLE, SC 29010-0251
PO BOX 252, BISHOPVILLE, SC 29010-0252
PO BOX 253, BISHOPVILLE, SC 29010-0253
PO BOX 254, BISHOPVILLE, SC 29010-0254
PO BOX 255, BISHOPVILLE, SC 29010-0255
PO BOX 256, BISHOPVILLE, SC 29010-0256
PO BOX 257, BISHOPVILLE, SC 29010-0257
PO BOX 258, BISHOPVILLE, SC 29010-0258
PO BOX 259, BISHOPVILLE, SC 29010-0259
PO BOX 260, BISHOPVILLE, SC 29010-0260
PO BOX 261, BISHOPVILLE, SC 29010-0261
PO BOX 262, BISHOPVILLE, SC 29010-0262
PO BOX 263, BISHOPVILLE, SC 29010-0263
PO BOX 264, BISHOPVILLE, SC 29010-0264
PO BOX 265, BISHOPVILLE, SC 29010-0265
PO BOX 266, BISHOPVILLE, SC 29010-0266
PO BOX 267, BISHOPVILLE, SC 29010-0267
PO BOX 268, BISHOPVILLE, SC 29010-0268
PO BOX 269, BISHOPVILLE, SC 29010-0269
PO BOX 270, BISHOPVILLE, SC 29010-0270
PO BOX 271, BISHOPVILLE, SC 29010-0271
PO BOX 272, BISHOPVILLE, SC 29010-0272
PO BOX 273, BISHOPVILLE, SC 29010-0273
PO BOX 274, BISHOPVILLE, SC 29010-0274
PO BOX 275, BISHOPVILLE, SC 29010-0275
PO BOX 276, BISHOPVILLE, SC 29010-0276
PO BOX 277, BISHOPVILLE, SC 29010-0277
PO BOX 278, BISHOPVILLE, SC 29010-0278
PO BOX 279, BISHOPVILLE, SC 29010-0279
PO BOX 280, BISHOPVILLE, SC 29010-0280
PO BOX 281, BISHOPVILLE, SC 29010-0281
PO BOX 282, BISHOPVILLE, SC 29010-0282
PO BOX 283, BISHOPVILLE, SC 29010-0283
PO BOX 284, BISHOPVILLE, SC 29010-0284
PO BOX 285, BISHOPVILLE, SC 29010-0285
PO BOX 286, BISHOPVILLE, SC 29010-0286
PO BOX 287, BISHOPVILLE, SC 29010-0287
PO BOX 288, BISHOPVILLE, SC 29010-0288
PO BOX 289, BISHOPVILLE, SC 29010-0289
PO BOX 290, BISHOPVILLE, SC 29010-0290
PO BOX 291, BISHOPVILLE, SC 29010-0291
PO BOX 292, BISHOPVILLE, SC 29010-0292
PO BOX 293, BISHOPVILLE, SC 29010-0293
PO BOX 294, BISHOPVILLE, SC 29010-0294
PO BOX 295, BISHOPVILLE, SC 29010-0295
PO BOX 296, BISHOPVILLE, SC 29010-0296
PO BOX 297, BISHOPVILLE, SC 29010-0297
PO BOX 298, BISHOPVILLE, SC 29010-0298
PO BOX 299, BISHOPVILLE, SC 29010-0299
PO BOX 300, BISHOPVILLE, SC 29010-0300
PO BOX 301, BISHOPVILLE, SC 29010-0301
PO BOX 302, BISHOPVILLE, SC 29010-0302
PO BOX 303, BISHOPVILLE, SC 29010-0303
PO BOX 304, BISHOPVILLE, SC 29010-0304
PO BOX 305, BISHOPVILLE, SC 29010-0305
PO BOX 306, BISHOPVILLE, SC 29010-0306
PO BOX 307, BISHOPVILLE, SC 29010-0307
PO BOX 308, BISHOPVILLE, SC 29010-0308
PO BOX 309, BISHOPVILLE, SC 29010-0309
PO BOX 310, BISHOPVILLE, SC 29010-0310
PO BOX 311, BISHOPVILLE, SC 29010-0311
PO BOX 312, BISHOPVILLE, SC 29010-0312
PO BOX 313, BISHOPVILLE, SC 29010-0313
PO BOX 314, BISHOPVILLE, SC 29010-0314
PO BOX 315, BISHOPVILLE, SC 29010-0315
PO BOX 316, BISHOPVILLE, SC 29010-0316
PO BOX 317, BISHOPVILLE, SC 29010-0317
PO BOX 318, BISHOPVILLE, SC 29010-0318
PO BOX 319, BISHOPVILLE, SC 29010-0319
PO BOX 320, BISHOPVILLE, SC 29010-0320
PO BOX 321, BISHOPVILLE, SC 29010-0321
PO BOX 322, BISHOPVILLE, SC 29010-0322
PO BOX 323, BISHOPVILLE, SC 29010-0323