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 441, COUNCIL BLUFFS, IA 51502-0441
PO BOX 442, COUNCIL BLUFFS, IA 51502-0442
PO BOX 443, COUNCIL BLUFFS, IA 51502-0443
PO BOX 444, COUNCIL BLUFFS, IA 51502-0444
PO BOX 445, COUNCIL BLUFFS, IA 51502-0445
PO BOX 446, COUNCIL BLUFFS, IA 51502-0446
PO BOX 447, COUNCIL BLUFFS, IA 51502-0447
PO BOX 448, COUNCIL BLUFFS, IA 51502-0448
PO BOX 449, COUNCIL BLUFFS, IA 51502-0449
PO BOX 450, COUNCIL BLUFFS, IA 51502-0450
PO BOX 451, COUNCIL BLUFFS, IA 51502-0451
PO BOX 452, COUNCIL BLUFFS, IA 51502-0452
PO BOX 453, COUNCIL BLUFFS, IA 51502-0453
PO BOX 454, COUNCIL BLUFFS, IA 51502-0454
PO BOX 455, COUNCIL BLUFFS, IA 51502-0455
PO BOX 456, COUNCIL BLUFFS, IA 51502-0456
PO BOX 457, COUNCIL BLUFFS, IA 51502-0457
PO BOX 458, COUNCIL BLUFFS, IA 51502-0458
PO BOX 459, COUNCIL BLUFFS, IA 51502-0459
PO BOX 460, COUNCIL BLUFFS, IA 51502-0460
PO BOX 461, COUNCIL BLUFFS, IA 51502-0461
PO BOX 462, COUNCIL BLUFFS, IA 51502-0462
PO BOX 463, COUNCIL BLUFFS, IA 51502-0463
PO BOX 464, COUNCIL BLUFFS, IA 51502-0464
PO BOX 465, COUNCIL BLUFFS, IA 51502-0465
PO BOX 466, COUNCIL BLUFFS, IA 51502-0466
PO BOX 467, COUNCIL BLUFFS, IA 51502-0467
PO BOX 468, COUNCIL BLUFFS, IA 51502-0468
PO BOX 469, COUNCIL BLUFFS, IA 51502-0469
PO BOX 470, COUNCIL BLUFFS, IA 51502-0470
PO BOX 471, COUNCIL BLUFFS, IA 51502-0471
PO BOX 472, COUNCIL BLUFFS, IA 51502-0472
PO BOX 473, COUNCIL BLUFFS, IA 51502-0473
PO BOX 474, COUNCIL BLUFFS, IA 51502-0474
PO BOX 475, COUNCIL BLUFFS, IA 51502-0475
PO BOX 476, COUNCIL BLUFFS, IA 51502-0476
PO BOX 477, COUNCIL BLUFFS, IA 51502-0477
PO BOX 478, COUNCIL BLUFFS, IA 51502-0478
PO BOX 479, COUNCIL BLUFFS, IA 51502-0479
PO BOX 480, COUNCIL BLUFFS, IA 51502-0480
PO BOX 481, COUNCIL BLUFFS, IA 51502-0481
PO BOX 482, COUNCIL BLUFFS, IA 51502-0482
PO BOX 483, COUNCIL BLUFFS, IA 51502-0483
PO BOX 484, COUNCIL BLUFFS, IA 51502-0484
PO BOX 485, COUNCIL BLUFFS, IA 51502-0485
PO BOX 486, COUNCIL BLUFFS, IA 51502-0486
PO BOX 487, COUNCIL BLUFFS, IA 51502-0487
PO BOX 488, COUNCIL BLUFFS, IA 51502-0488
PO BOX 489, COUNCIL BLUFFS, IA 51502-0489
PO BOX 490, COUNCIL BLUFFS, IA 51502-0490
PO BOX 491, COUNCIL BLUFFS, IA 51502-0491
PO BOX 492, COUNCIL BLUFFS, IA 51502-0492
PO BOX 493, COUNCIL BLUFFS, IA 51502-0493
PO BOX 494, COUNCIL BLUFFS, IA 51502-0494
PO BOX 495, COUNCIL BLUFFS, IA 51502-0495
PO BOX 496, COUNCIL BLUFFS, IA 51502-0496
PO BOX 497, COUNCIL BLUFFS, IA 51502-0497
PO BOX 498, COUNCIL BLUFFS, IA 51502-0498
PO BOX 499, COUNCIL BLUFFS, IA 51502-0499
PO BOX 500, COUNCIL BLUFFS, IA 51502-0500
PO BOX 501, COUNCIL BLUFFS, IA 51502-0501
PO BOX 502, COUNCIL BLUFFS, IA 51502-0502
PO BOX 503, COUNCIL BLUFFS, IA 51502-0503
PO BOX 504, COUNCIL BLUFFS, IA 51502-0504
PO BOX 505, COUNCIL BLUFFS, IA 51502-0505
PO BOX 506, COUNCIL BLUFFS, IA 51502-0506
PO BOX 507, COUNCIL BLUFFS, IA 51502-0507
PO BOX 508, COUNCIL BLUFFS, IA 51502-0508
PO BOX 509, COUNCIL BLUFFS, IA 51502-0509
PO BOX 510, COUNCIL BLUFFS, IA 51502-0510
PO BOX 511, COUNCIL BLUFFS, IA 51502-0511
PO BOX 512, COUNCIL BLUFFS, IA 51502-0512
PO BOX 513, COUNCIL BLUFFS, IA 51502-0513
PO BOX 514, COUNCIL BLUFFS, IA 51502-0514
PO BOX 515, COUNCIL BLUFFS, IA 51502-0515
PO BOX 516, COUNCIL BLUFFS, IA 51502-0516
PO BOX 517, COUNCIL BLUFFS, IA 51502-0517
PO BOX 518, COUNCIL BLUFFS, IA 51502-0518
PO BOX 519, COUNCIL BLUFFS, IA 51502-0519
PO BOX 520, COUNCIL BLUFFS, IA 51502-0520
PO BOX 521, COUNCIL BLUFFS, IA 51502-0521
PO BOX 522, COUNCIL BLUFFS, IA 51502-0522
PO BOX 523, COUNCIL BLUFFS, IA 51502-0523
PO BOX 524, COUNCIL BLUFFS, IA 51502-0524
PO BOX 525, COUNCIL BLUFFS, IA 51502-0525
PO BOX 526, COUNCIL BLUFFS, IA 51502-0526
PO BOX 527, COUNCIL BLUFFS, IA 51502-0527
PO BOX 528, COUNCIL BLUFFS, IA 51502-0528
PO BOX 529, COUNCIL BLUFFS, IA 51502-0529
PO BOX 530, COUNCIL BLUFFS, IA 51502-0530
PO BOX 531, COUNCIL BLUFFS, IA 51502-0531
PO BOX 532, COUNCIL BLUFFS, IA 51502-0532
PO BOX 533, COUNCIL BLUFFS, IA 51502-0533
PO BOX 534, COUNCIL BLUFFS, IA 51502-0534
PO BOX 535, COUNCIL BLUFFS, IA 51502-0535
PO BOX 536, COUNCIL BLUFFS, IA 51502-0536
PO BOX 537, COUNCIL BLUFFS, IA 51502-0537
PO BOX 538, COUNCIL BLUFFS, IA 51502-0538
PO BOX 539, COUNCIL BLUFFS, IA 51502-0539
PO BOX 540, COUNCIL BLUFFS, IA 51502-0540
PO BOX 541, COUNCIL BLUFFS, IA 51502-0541
PO BOX 542, COUNCIL BLUFFS, IA 51502-0542
PO BOX 543, COUNCIL BLUFFS, IA 51502-0543
PO BOX 544, COUNCIL BLUFFS, IA 51502-0544
PO BOX 545, COUNCIL BLUFFS, IA 51502-0545
PO BOX 546, COUNCIL BLUFFS, IA 51502-0546
PO BOX 547, COUNCIL BLUFFS, IA 51502-0547
PO BOX 548, COUNCIL BLUFFS, IA 51502-0548
PO BOX 549, COUNCIL BLUFFS, IA 51502-0549
PO BOX 550, COUNCIL BLUFFS, IA 51502-0550
PO BOX 551, COUNCIL BLUFFS, IA 51502-0551
PO BOX 552, COUNCIL BLUFFS, IA 51502-0552
PO BOX 553, COUNCIL BLUFFS, IA 51502-0553
PO BOX 554, COUNCIL BLUFFS, IA 51502-0554
PO BOX 555, COUNCIL BLUFFS, IA 51502-0555
PO BOX 556, COUNCIL BLUFFS, IA 51502-0556
PO BOX 557, COUNCIL BLUFFS, IA 51502-0557
PO BOX 558, COUNCIL BLUFFS, IA 51502-0558
PO BOX 559, COUNCIL BLUFFS, IA 51502-0559
PO BOX 560, COUNCIL BLUFFS, IA 51502-0560
PO BOX 561, COUNCIL BLUFFS, IA 51502-0561
PO BOX 562, COUNCIL BLUFFS, IA 51502-0562
PO BOX 563, COUNCIL BLUFFS, IA 51502-0563
PO BOX 564, COUNCIL BLUFFS, IA 51502-0564
PO BOX 565, COUNCIL BLUFFS, IA 51502-0565
PO BOX 566, COUNCIL BLUFFS, IA 51502-0566
PO BOX 567, COUNCIL BLUFFS, IA 51502-0567
PO BOX 568, COUNCIL BLUFFS, IA 51502-0568
PO BOX 569, COUNCIL BLUFFS, IA 51502-0569
PO BOX 570, COUNCIL BLUFFS, IA 51502-0570
PO BOX 571, COUNCIL BLUFFS, IA 51502-0571
PO BOX 572, COUNCIL BLUFFS, IA 51502-0572
PO BOX 573, COUNCIL BLUFFS, IA 51502-0573
PO BOX 574, COUNCIL BLUFFS, IA 51502-0574
PO BOX 575, COUNCIL BLUFFS, IA 51502-0575
PO BOX 576, COUNCIL BLUFFS, IA 51502-0576
PO BOX 577, COUNCIL BLUFFS, IA 51502-0577
PO BOX 578, COUNCIL BLUFFS, IA 51502-0578
PO BOX 579, COUNCIL BLUFFS, IA 51502-0579
PO BOX 580, COUNCIL BLUFFS, IA 51502-0580
PO BOX 581, COUNCIL BLUFFS, IA 51502-0581
PO BOX 582, COUNCIL BLUFFS, IA 51502-0582
PO BOX 583, COUNCIL BLUFFS, IA 51502-0583
PO BOX 584, COUNCIL BLUFFS, IA 51502-0584
PO BOX 585, COUNCIL BLUFFS, IA 51502-0585
PO BOX 586, COUNCIL BLUFFS, IA 51502-0586
PO BOX 587, COUNCIL BLUFFS, IA 51502-0587
PO BOX 588, COUNCIL BLUFFS, IA 51502-0588
PO BOX 589, COUNCIL BLUFFS, IA 51502-0589
PO BOX 590, COUNCIL BLUFFS, IA 51502-0590
PO BOX 591, COUNCIL BLUFFS, IA 51502-0591
PO BOX 592, COUNCIL BLUFFS, IA 51502-0592
PO BOX 593, COUNCIL BLUFFS, IA 51502-0593
PO BOX 594, COUNCIL BLUFFS, IA 51502-0594
PO BOX 595, COUNCIL BLUFFS, IA 51502-0595
PO BOX 596, COUNCIL BLUFFS, IA 51502-0596
PO BOX 597, COUNCIL BLUFFS, IA 51502-0597
PO BOX 598, COUNCIL BLUFFS, IA 51502-0598
PO BOX 599, COUNCIL BLUFFS, IA 51502-0599
PO BOX 600, COUNCIL BLUFFS, IA 51502-0600
PO BOX 601, COUNCIL BLUFFS, IA 51502-0601
PO BOX 602, COUNCIL BLUFFS, IA 51502-0602
PO BOX 603, COUNCIL BLUFFS, IA 51502-0603
PO BOX 604, COUNCIL BLUFFS, IA 51502-0604
PO BOX 605, COUNCIL BLUFFS, IA 51502-0605
PO BOX 606, COUNCIL BLUFFS, IA 51502-0606
PO BOX 607, COUNCIL BLUFFS, IA 51502-0607
PO BOX 608, COUNCIL BLUFFS, IA 51502-0608
PO BOX 609, COUNCIL BLUFFS, IA 51502-0609
PO BOX 610, COUNCIL BLUFFS, IA 51502-0610
PO BOX 611, COUNCIL BLUFFS, IA 51502-0611
PO BOX 612, COUNCIL BLUFFS, IA 51502-0612
PO BOX 613, COUNCIL BLUFFS, IA 51502-0613
PO BOX 614, COUNCIL BLUFFS, IA 51502-0614
PO BOX 615, COUNCIL BLUFFS, IA 51502-0615
PO BOX 616, COUNCIL BLUFFS, IA 51502-0616
PO BOX 617, COUNCIL BLUFFS, IA 51502-0617
PO BOX 618, COUNCIL BLUFFS, IA 51502-0618
PO BOX 619, COUNCIL BLUFFS, IA 51502-0619
PO BOX 620, COUNCIL BLUFFS, IA 51502-0620
PO BOX 621, COUNCIL BLUFFS, IA 51502-0621
PO BOX 622, COUNCIL BLUFFS, IA 51502-0622
PO BOX 623, COUNCIL BLUFFS, IA 51502-0623
PO BOX 624, COUNCIL BLUFFS, IA 51502-0624
PO BOX 625, COUNCIL BLUFFS, IA 51502-0625
PO BOX 626, COUNCIL BLUFFS, IA 51502-0626
PO BOX 627, COUNCIL BLUFFS, IA 51502-0627
PO BOX 628, COUNCIL BLUFFS, IA 51502-0628
PO BOX 629, COUNCIL BLUFFS, IA 51502-0629
PO BOX 630, COUNCIL BLUFFS, IA 51502-0630
PO BOX 631, COUNCIL BLUFFS, IA 51502-0631
PO BOX 632, COUNCIL BLUFFS, IA 51502-0632
PO BOX 633, COUNCIL BLUFFS, IA 51502-0633
PO BOX 634, COUNCIL BLUFFS, IA 51502-0634
PO BOX 635, COUNCIL BLUFFS, IA 51502-0635
PO BOX 636, COUNCIL BLUFFS, IA 51502-0636
PO BOX 637, COUNCIL BLUFFS, IA 51502-0637
PO BOX 638, COUNCIL BLUFFS, IA 51502-0638
PO BOX 639, COUNCIL BLUFFS, IA 51502-0639
PO BOX 640, COUNCIL BLUFFS, IA 51502-0640
PO BOX 641, COUNCIL BLUFFS, IA 51502-0641