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 6000, FORT SMITH, AR 72906-6000
PO BOX 6001, FORT SMITH, AR 72906-6001
PO BOX 6002, FORT SMITH, AR 72906-6002
PO BOX 6003, FORT SMITH, AR 72906-6003
PO BOX 6004, FORT SMITH, AR 72906-6004
PO BOX 6005, FORT SMITH, AR 72906-6005
PO BOX 6006, FORT SMITH, AR 72906-6006
PO BOX 6007, FORT SMITH, AR 72906-6007
PO BOX 6008, FORT SMITH, AR 72906-6008
PO BOX 6009, FORT SMITH, AR 72906-6009
PO BOX 6010, FORT SMITH, AR 72906-6010
PO BOX 6011, FORT SMITH, AR 72906-6011
PO BOX 6012, FORT SMITH, AR 72906-6012
PO BOX 6013, FORT SMITH, AR 72906-6013
PO BOX 6014, FORT SMITH, AR 72906-6014
PO BOX 6015, FORT SMITH, AR 72906-6015
PO BOX 6016, FORT SMITH, AR 72906-6016
PO BOX 6017, FORT SMITH, AR 72906-6017
PO BOX 6018, FORT SMITH, AR 72906-6018
PO BOX 6019, FORT SMITH, AR 72906-6019
PO BOX 6020, FORT SMITH, AR 72906-6020
PO BOX 6021, FORT SMITH, AR 72906-6021
PO BOX 6022, FORT SMITH, AR 72906-6022
PO BOX 6023, FORT SMITH, AR 72906-6023
PO BOX 6024, FORT SMITH, AR 72906-6024
PO BOX 6025, FORT SMITH, AR 72906-6025
PO BOX 6026, FORT SMITH, AR 72906-6026
PO BOX 6027, FORT SMITH, AR 72906-6027
PO BOX 6028, FORT SMITH, AR 72906-6028
PO BOX 6029, FORT SMITH, AR 72906-6029
PO BOX 6030, FORT SMITH, AR 72906-6030
PO BOX 6031, FORT SMITH, AR 72906-6031
PO BOX 6032, FORT SMITH, AR 72906-6032
PO BOX 6033, FORT SMITH, AR 72906-6033
PO BOX 6034, FORT SMITH, AR 72906-6034
PO BOX 6035, FORT SMITH, AR 72906-6035
PO BOX 6036, FORT SMITH, AR 72906-6036
PO BOX 6037, FORT SMITH, AR 72906-6037
PO BOX 6038, FORT SMITH, AR 72906-6038
PO BOX 6039, FORT SMITH, AR 72906-6039
PO BOX 6040, FORT SMITH, AR 72906-6040
PO BOX 6041, FORT SMITH, AR 72906-6041
PO BOX 6042, FORT SMITH, AR 72906-6042
PO BOX 6043, FORT SMITH, AR 72906-6043
PO BOX 6044, FORT SMITH, AR 72906-6044
PO BOX 6045, FORT SMITH, AR 72906-6045
PO BOX 6046, FORT SMITH, AR 72906-6046
PO BOX 6047, FORT SMITH, AR 72906-6047
PO BOX 6048, FORT SMITH, AR 72906-6048
PO BOX 6049, FORT SMITH, AR 72906-6049
PO BOX 6050, FORT SMITH, AR 72906-6050
PO BOX 6051, FORT SMITH, AR 72906-6051
PO BOX 6052, FORT SMITH, AR 72906-6052
PO BOX 6053, FORT SMITH, AR 72906-6053
PO BOX 6054, FORT SMITH, AR 72906-6054
PO BOX 6055, FORT SMITH, AR 72906-6055
PO BOX 6056, FORT SMITH, AR 72906-6056
PO BOX 6057, FORT SMITH, AR 72906-6057
PO BOX 6058, FORT SMITH, AR 72906-6058
PO BOX 6059, FORT SMITH, AR 72906-6059
PO BOX 6060, FORT SMITH, AR 72906-6060
PO BOX 6061, FORT SMITH, AR 72906-6061
PO BOX 6062, FORT SMITH, AR 72906-6062
PO BOX 6063, FORT SMITH, AR 72906-6063
PO BOX 6064, FORT SMITH, AR 72906-6064
PO BOX 6065, FORT SMITH, AR 72906-6065
PO BOX 6066, FORT SMITH, AR 72906-6066
PO BOX 6067, FORT SMITH, AR 72906-6067
PO BOX 6068, FORT SMITH, AR 72906-6068
PO BOX 6069, FORT SMITH, AR 72906-6069
PO BOX 6070, FORT SMITH, AR 72906-6070
PO BOX 6071, FORT SMITH, AR 72906-6071
PO BOX 6072, FORT SMITH, AR 72906-6072
PO BOX 6073, FORT SMITH, AR 72906-6073
PO BOX 6074, FORT SMITH, AR 72906-6074
PO BOX 6075, FORT SMITH, AR 72906-6075
PO BOX 6076, FORT SMITH, AR 72906-6076
PO BOX 6077, FORT SMITH, AR 72906-6077
PO BOX 6078, FORT SMITH, AR 72906-6078
PO BOX 6079, FORT SMITH, AR 72906-6079
PO BOX 6080, FORT SMITH, AR 72906-6080
PO BOX 6081, FORT SMITH, AR 72906-6081
PO BOX 6082, FORT SMITH, AR 72906-6082
PO BOX 6083, FORT SMITH, AR 72906-6083
PO BOX 6084, FORT SMITH, AR 72906-6084
PO BOX 6085, FORT SMITH, AR 72906-6085
PO BOX 6086, FORT SMITH, AR 72906-6086
PO BOX 6087, FORT SMITH, AR 72906-6087
PO BOX 6088, FORT SMITH, AR 72906-6088
PO BOX 6089, FORT SMITH, AR 72906-6089
PO BOX 6090, FORT SMITH, AR 72906-6090
PO BOX 6091, FORT SMITH, AR 72906-6091
PO BOX 6092, FORT SMITH, AR 72906-6092
PO BOX 6093, FORT SMITH, AR 72906-6093
PO BOX 6094, FORT SMITH, AR 72906-6094
PO BOX 6095, FORT SMITH, AR 72906-6095
PO BOX 6096, FORT SMITH, AR 72906-6096
PO BOX 6097, FORT SMITH, AR 72906-6097
PO BOX 6098, FORT SMITH, AR 72906-6098
PO BOX 6099, FORT SMITH, AR 72906-6099
PO BOX 6100, FORT SMITH, AR 72906-6100
PO BOX 6101, FORT SMITH, AR 72906-6101
PO BOX 6102, FORT SMITH, AR 72906-6102
PO BOX 6103, FORT SMITH, AR 72906-6103
PO BOX 6104, FORT SMITH, AR 72906-6104
PO BOX 6105, FORT SMITH, AR 72906-6105
PO BOX 6106, FORT SMITH, AR 72906-6106
PO BOX 6107, FORT SMITH, AR 72906-6107
PO BOX 6108, FORT SMITH, AR 72906-6108
PO BOX 6109, FORT SMITH, AR 72906-6109
PO BOX 6110, FORT SMITH, AR 72906-6110
PO BOX 6111, FORT SMITH, AR 72906-6111
PO BOX 6112, FORT SMITH, AR 72906-6112
PO BOX 6113, FORT SMITH, AR 72906-6113
PO BOX 6114, FORT SMITH, AR 72906-6114
PO BOX 6115, FORT SMITH, AR 72906-6115
PO BOX 6116, FORT SMITH, AR 72906-6116
PO BOX 6117, FORT SMITH, AR 72906-6117
PO BOX 6118, FORT SMITH, AR 72906-6118
PO BOX 6119, FORT SMITH, AR 72906-6119
PO BOX 6120, FORT SMITH, AR 72906-6120
PO BOX 6121, FORT SMITH, AR 72906-6121
PO BOX 6122, FORT SMITH, AR 72906-6122
PO BOX 6123, FORT SMITH, AR 72906-6123
PO BOX 6124, FORT SMITH, AR 72906-6124
PO BOX 6125, FORT SMITH, AR 72906-6125
PO BOX 6126, FORT SMITH, AR 72906-6126
PO BOX 6127, FORT SMITH, AR 72906-6127
PO BOX 6128, FORT SMITH, AR 72906-6128
PO BOX 6129, FORT SMITH, AR 72906-6129
PO BOX 6130, FORT SMITH, AR 72906-6130
PO BOX 6131, FORT SMITH, AR 72906-6131
PO BOX 6132, FORT SMITH, AR 72906-6132
PO BOX 6133, FORT SMITH, AR 72906-6133
PO BOX 6134, FORT SMITH, AR 72906-6134
PO BOX 6135, FORT SMITH, AR 72906-6135
PO BOX 6136, FORT SMITH, AR 72906-6136
PO BOX 6137, FORT SMITH, AR 72906-6137
PO BOX 6138, FORT SMITH, AR 72906-6138
PO BOX 6139, FORT SMITH, AR 72906-6139
PO BOX 6140, FORT SMITH, AR 72906-6140
PO BOX 6141, FORT SMITH, AR 72906-6141
PO BOX 6142, FORT SMITH, AR 72906-6142
PO BOX 6143, FORT SMITH, AR 72906-6143
PO BOX 6144, FORT SMITH, AR 72906-6144
PO BOX 6145, FORT SMITH, AR 72906-6145
PO BOX 6146, FORT SMITH, AR 72906-6146
PO BOX 6147, FORT SMITH, AR 72906-6147
PO BOX 6148, FORT SMITH, AR 72906-6148
PO BOX 6149, FORT SMITH, AR 72906-6149
PO BOX 6150, FORT SMITH, AR 72906-6150
PO BOX 6151, FORT SMITH, AR 72906-6151
PO BOX 6152, FORT SMITH, AR 72906-6152
PO BOX 6153, FORT SMITH, AR 72906-6153
PO BOX 6154, FORT SMITH, AR 72906-6154
PO BOX 6155, FORT SMITH, AR 72906-6155
PO BOX 6156, FORT SMITH, AR 72906-6156
PO BOX 6157, FORT SMITH, AR 72906-6157
PO BOX 6158, FORT SMITH, AR 72906-6158
PO BOX 6159, FORT SMITH, AR 72906-6159
PO BOX 6160, FORT SMITH, AR 72906-6160
PO BOX 6161, FORT SMITH, AR 72906-6161
PO BOX 6162, FORT SMITH, AR 72906-6162
PO BOX 6163, FORT SMITH, AR 72906-6163
PO BOX 6164, FORT SMITH, AR 72906-6164