A PO BOX number can be less than or more than four digit. For post office boxes, the general rule is that each box has its own ZIP+4 code.
The last four digit is often one of the following:
1. Zero plus the last three digits of the box number (eg. PO BOX 1001, Los Angeles CA 90001-0001).
2. The last four digits of the box number (eg. PO BOX 9991, Twin Peaks CA 92391-9991).
3. If the box number is less than four digits, enough zeros prepended to the front of the box number to produce a four-digit number(eg. PO BOX 1, Shreveport LA 71161-0001).
However, there is no uniform rule, the zip code plus four is for reference only, the ZIP+4 code must be looked up individually for each box in the USPS offical website.
PO BOX 371301, PITTSBURGH, PA 15250-7301
PO BOX 371302, PITTSBURGH, PA 15250-7302
PO BOX 371303, PITTSBURGH, PA 15250-7303
PO BOX 371304, PITTSBURGH, PA 15250-7304
PO BOX 371305, PITTSBURGH, PA 15250-7305
PO BOX 371306, PITTSBURGH, PA 15250-7306
PO BOX 371307, PITTSBURGH, PA 15250-7307
PO BOX 371308, PITTSBURGH, PA 15250-7308
PO BOX 371309, PITTSBURGH, PA 15250-7309
PO BOX 371310, PITTSBURGH, PA 15250-7310
PO BOX 371311, PITTSBURGH, PA 15250-7311
PO BOX 371312, PITTSBURGH, PA 15250-7312
PO BOX 371313, PITTSBURGH, PA 15250-7313
PO BOX 371314, PITTSBURGH, PA 15250-7314
PO BOX 371315, PITTSBURGH, PA 15250-7315
PO BOX 371316, PITTSBURGH, PA 15250-7316
PO BOX 371317, PITTSBURGH, PA 15250-7317
PO BOX 371318, PITTSBURGH, PA 15250-7318
PO BOX 371319, PITTSBURGH, PA 15250-7319
PO BOX 371320, PITTSBURGH, PA 15250-7320
PO BOX 371321, PITTSBURGH, PA 15250-7321
PO BOX 371322, PITTSBURGH, PA 15250-7322
PO BOX 371323, PITTSBURGH, PA 15250-7323
PO BOX 371324, PITTSBURGH, PA 15250-7324
PO BOX 371325, PITTSBURGH, PA 15250-7325
PO BOX 371326, PITTSBURGH, PA 15250-7326
PO BOX 371327, PITTSBURGH, PA 15250-7327
PO BOX 371328, PITTSBURGH, PA 15250-7328
PO BOX 371329, PITTSBURGH, PA 15250-7329
PO BOX 371330, PITTSBURGH, PA 15250-7330
PO BOX 371331, PITTSBURGH, PA 15250-7331
PO BOX 371332, PITTSBURGH, PA 15250-7332
PO BOX 371333, PITTSBURGH, PA 15250-7333
PO BOX 371334, PITTSBURGH, PA 15250-7334
PO BOX 371335, PITTSBURGH, PA 15250-7335
PO BOX 371336, PITTSBURGH, PA 15250-7336
PO BOX 371337, PITTSBURGH, PA 15250-7337
PO BOX 371338, PITTSBURGH, PA 15250-7338
PO BOX 371339, PITTSBURGH, PA 15250-7339
PO BOX 371340, PITTSBURGH, PA 15250-7340
PO BOX 371341, PITTSBURGH, PA 15250-7341
PO BOX 371342, PITTSBURGH, PA 15250-7342
PO BOX 371343, PITTSBURGH, PA 15250-7343
PO BOX 371344, PITTSBURGH, PA 15250-7344
PO BOX 371345, PITTSBURGH, PA 15250-7345
PO BOX 371346, PITTSBURGH, PA 15250-7346
PO BOX 371347, PITTSBURGH, PA 15250-7347
PO BOX 371348, PITTSBURGH, PA 15250-7348
PO BOX 371349, PITTSBURGH, PA 15250-7349
PO BOX 371350, PITTSBURGH, PA 15250-7350
PO BOX 371351, PITTSBURGH, PA 15250-7351
PO BOX 371352, PITTSBURGH, PA 15250-7352
PO BOX 371353, PITTSBURGH, PA 15250-7353
PO BOX 371354, PITTSBURGH, PA 15250-7354
PO BOX 371355, PITTSBURGH, PA 15250-7355
PO BOX 371356, PITTSBURGH, PA 15250-7356
PO BOX 371357, PITTSBURGH, PA 15250-7357
PO BOX 371358, PITTSBURGH, PA 15250-7358
PO BOX 371359, PITTSBURGH, PA 15250-7359
PO BOX 371360, PITTSBURGH, PA 15250-7360
PO BOX 371361, PITTSBURGH, PA 15250-7361
PO BOX 371362, PITTSBURGH, PA 15250-7362
PO BOX 371363, PITTSBURGH, PA 15250-7363
PO BOX 371364, PITTSBURGH, PA 15250-7364
PO BOX 371365, PITTSBURGH, PA 15250-7365
PO BOX 371366, PITTSBURGH, PA 15250-7366
PO BOX 371367, PITTSBURGH, PA 15250-7367
PO BOX 371368, PITTSBURGH, PA 15250-7368
PO BOX 371369, PITTSBURGH, PA 15250-7369
PO BOX 371370, PITTSBURGH, PA 15250-7370
PO BOX 371371, PITTSBURGH, PA 15250-7371
PO BOX 371372, PITTSBURGH, PA 15250-7372
PO BOX 371373, PITTSBURGH, PA 15250-7373
PO BOX 371374, PITTSBURGH, PA 15250-7374
PO BOX 371375, PITTSBURGH, PA 15250-7375
PO BOX 371376, PITTSBURGH, PA 15250-7376
PO BOX 371377, PITTSBURGH, PA 15250-7377
PO BOX 371378, PITTSBURGH, PA 15250-7378
PO BOX 371379, PITTSBURGH, PA 15250-7379
PO BOX 371380, PITTSBURGH, PA 15250-7380
PO BOX 371381, PITTSBURGH, PA 15250-7381
PO BOX 371382, PITTSBURGH, PA 15250-7382
PO BOX 371383, PITTSBURGH, PA 15250-7383
PO BOX 371384, PITTSBURGH, PA 15250-7384
PO BOX 371385, PITTSBURGH, PA 15250-7385
PO BOX 371386, PITTSBURGH, PA 15250-7386
PO BOX 371387, PITTSBURGH, PA 15250-7387
PO BOX 371388, PITTSBURGH, PA 15250-7388
PO BOX 371389, PITTSBURGH, PA 15250-7389
PO BOX 371390, PITTSBURGH, PA 15250-7390
PO BOX 371391, PITTSBURGH, PA 15250-7391
PO BOX 371392, PITTSBURGH, PA 15250-7392
PO BOX 371393, PITTSBURGH, PA 15250-7393
PO BOX 371394, PITTSBURGH, PA 15250-7394
PO BOX 371395, PITTSBURGH, PA 15250-7395
PO BOX 371396, PITTSBURGH, PA 15250-7396
PO BOX 371397, PITTSBURGH, PA 15250-7397
PO BOX 371398, PITTSBURGH, PA 15250-7398
PO BOX 371399, PITTSBURGH, PA 15250-7399
PO BOX 371400, PITTSBURGH, PA 15250-7400
PO BOX 371401, PITTSBURGH, PA 15250-7401
PO BOX 371402, PITTSBURGH, PA 15250-7402
PO BOX 371403, PITTSBURGH, PA 15250-7403
PO BOX 371404, PITTSBURGH, PA 15250-7404
PO BOX 371405, PITTSBURGH, PA 15250-7405
PO BOX 371406, PITTSBURGH, PA 15250-7406
PO BOX 371407, PITTSBURGH, PA 15250-7407
PO BOX 371408, PITTSBURGH, PA 15250-7408
PO BOX 371409, PITTSBURGH, PA 15250-7409
PO BOX 371410, PITTSBURGH, PA 15250-7410
PO BOX 371411, PITTSBURGH, PA 15250-7411
PO BOX 371412, PITTSBURGH, PA 15250-7412
PO BOX 371413, PITTSBURGH, PA 15250-7413
PO BOX 371414, PITTSBURGH, PA 15250-7414
PO BOX 371415, PITTSBURGH, PA 15250-7415
PO BOX 371416, PITTSBURGH, PA 15250-7416
PO BOX 371417, PITTSBURGH, PA 15250-7417
PO BOX 371418, PITTSBURGH, PA 15250-7418
PO BOX 371419, PITTSBURGH, PA 15250-7419
PO BOX 371420, PITTSBURGH, PA 15250-7420
PO BOX 371421, PITTSBURGH, PA 15250-7421
PO BOX 371422, PITTSBURGH, PA 15250-7422
PO BOX 371423, PITTSBURGH, PA 15250-7423
PO BOX 371424, PITTSBURGH, PA 15250-7424
PO BOX 371425, PITTSBURGH, PA 15250-7425
PO BOX 371426, PITTSBURGH, PA 15250-7426
PO BOX 371427, PITTSBURGH, PA 15250-7427
PO BOX 371428, PITTSBURGH, PA 15250-7428
PO BOX 371429, PITTSBURGH, PA 15250-7429
PO BOX 371430, PITTSBURGH, PA 15250-7430
PO BOX 371431, PITTSBURGH, PA 15250-7431
PO BOX 371432, PITTSBURGH, PA 15250-7432
PO BOX 371433, PITTSBURGH, PA 15250-7433
PO BOX 371434, PITTSBURGH, PA 15250-7434
PO BOX 371435, PITTSBURGH, PA 15250-7435
PO BOX 371436, PITTSBURGH, PA 15250-7436
PO BOX 371437, PITTSBURGH, PA 15250-7437
PO BOX 371438, PITTSBURGH, PA 15250-7438
PO BOX 371439, PITTSBURGH, PA 15250-7439
PO BOX 371440, PITTSBURGH, PA 15250-7440
PO BOX 371441, PITTSBURGH, PA 15250-7441
PO BOX 371442, PITTSBURGH, PA 15250-7442
PO BOX 371443, PITTSBURGH, PA 15250-7443
PO BOX 371444, PITTSBURGH, PA 15250-7444
PO BOX 371445, PITTSBURGH, PA 15250-7445
PO BOX 371446, PITTSBURGH, PA 15250-7446
PO BOX 371447, PITTSBURGH, PA 15250-7447
PO BOX 371448, PITTSBURGH, PA 15250-7448
PO BOX 371449, PITTSBURGH, PA 15250-7449
PO BOX 371450, PITTSBURGH, PA 15250-7450
PO BOX 371451, PITTSBURGH, PA 15250-7451
PO BOX 371452, PITTSBURGH, PA 15250-7452
PO BOX 371453, PITTSBURGH, PA 15250-7453
PO BOX 371454, PITTSBURGH, PA 15250-7454
PO BOX 371455, PITTSBURGH, PA 15250-7455
PO BOX 371456, PITTSBURGH, PA 15250-7456
PO BOX 371457, PITTSBURGH, PA 15250-7457
PO BOX 371458, PITTSBURGH, PA 15250-7458
PO BOX 371459, PITTSBURGH, PA 15250-7459
PO BOX 371460, PITTSBURGH, PA 15250-7460
PO BOX 371461, PITTSBURGH, PA 15250-7461
PO BOX 371462, PITTSBURGH, PA 15250-7462
PO BOX 371463, PITTSBURGH, PA 15250-7463
PO BOX 371464, PITTSBURGH, PA 15250-7464
PO BOX 371465, PITTSBURGH, PA 15250-7465
PO BOX 371466, PITTSBURGH, PA 15250-7466
PO BOX 371467, PITTSBURGH, PA 15250-7467
PO BOX 371468, PITTSBURGH, PA 15250-7468
PO BOX 371469, PITTSBURGH, PA 15250-7469
PO BOX 371470, PITTSBURGH, PA 15250-7470
PO BOX 371471, PITTSBURGH, PA 15250-7471
PO BOX 371472, PITTSBURGH, PA 15250-7472
PO BOX 371473, PITTSBURGH, PA 15250-7473
PO BOX 371474, PITTSBURGH, PA 15250-7474
PO BOX 371475, PITTSBURGH, PA 15250-7475
PO BOX 371476, PITTSBURGH, PA 15250-7476
PO BOX 371477, PITTSBURGH, PA 15250-7477
PO BOX 371478, PITTSBURGH, PA 15250-7478
PO BOX 371479, PITTSBURGH, PA 15250-7479
PO BOX 371480, PITTSBURGH, PA 15250-7480
PO BOX 371481, PITTSBURGH, PA 15250-7481
PO BOX 371482, PITTSBURGH, PA 15250-7482
PO BOX 371483, PITTSBURGH, PA 15250-7483
PO BOX 371484, PITTSBURGH, PA 15250-7484
PO BOX 371485, PITTSBURGH, PA 15250-7485
PO BOX 371486, PITTSBURGH, PA 15250-7486
PO BOX 371487, PITTSBURGH, PA 15250-7487
PO BOX 371488, PITTSBURGH, PA 15250-7488
PO BOX 371489, PITTSBURGH, PA 15250-7489
PO BOX 371490, PITTSBURGH, PA 15250-7490
PO BOX 371491, PITTSBURGH, PA 15250-7491
PO BOX 371492, PITTSBURGH, PA 15250-7492
PO BOX 371493, PITTSBURGH, PA 15250-7493
PO BOX 371494, PITTSBURGH, PA 15250-7494
PO BOX 371495, PITTSBURGH, PA 15250-7495
PO BOX 371496, PITTSBURGH, PA 15250-7496
PO BOX 371497, PITTSBURGH, PA 15250-7497
PO BOX 371498, PITTSBURGH, PA 15250-7498
PO BOX 371499, PITTSBURGH, PA 15250-7499
PO BOX 371500, PITTSBURGH, PA 15250-7500
PO BOX 371501, PITTSBURGH, PA 15250-7501