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 933, CHICO, CA 95927-0933
PO BOX 934, CHICO, CA 95927-0934
PO BOX 935, CHICO, CA 95927-0935
PO BOX 936, CHICO, CA 95927-0936
PO BOX 937, CHICO, CA 95927-0937
PO BOX 938, CHICO, CA 95927-0938
PO BOX 939, CHICO, CA 95927-0939
PO BOX 940, CHICO, CA 95927-0940
PO BOX 941, CHICO, CA 95927-0941
PO BOX 942, CHICO, CA 95927-0942
PO BOX 943, CHICO, CA 95927-0943
PO BOX 944, CHICO, CA 95927-0944
PO BOX 945, CHICO, CA 95927-0945
PO BOX 946, CHICO, CA 95927-0946
PO BOX 947, CHICO, CA 95927-0947
PO BOX 948, CHICO, CA 95927-0948
PO BOX 949, CHICO, CA 95927-0949
PO BOX 950, CHICO, CA 95927-0950
PO BOX 951, CHICO, CA 95927-0951
PO BOX 952, CHICO, CA 95927-0952
PO BOX 953, CHICO, CA 95927-0953
PO BOX 954, CHICO, CA 95927-0954
PO BOX 955, CHICO, CA 95927-0955
PO BOX 956, CHICO, CA 95927-0956
PO BOX 957, CHICO, CA 95927-0957
PO BOX 958, CHICO, CA 95927-0958
PO BOX 959, CHICO, CA 95927-0959
PO BOX 960, CHICO, CA 95927-0960
PO BOX 961, CHICO, CA 95927-0961
PO BOX 962, CHICO, CA 95927-0962
PO BOX 963, CHICO, CA 95927-0963
PO BOX 964, CHICO, CA 95927-0964
PO BOX 965, CHICO, CA 95927-0965
PO BOX 966, CHICO, CA 95927-0966
PO BOX 967, CHICO, CA 95927-0967
PO BOX 968, CHICO, CA 95927-0968
PO BOX 969, CHICO, CA 95927-0969
PO BOX 970, CHICO, CA 95927-0970
PO BOX 971, CHICO, CA 95927-0971
PO BOX 972, CHICO, CA 95927-0972
PO BOX 973, CHICO, CA 95927-0973
PO BOX 974, CHICO, CA 95927-0974
PO BOX 975, CHICO, CA 95927-0975
PO BOX 976, CHICO, CA 95927-0976
PO BOX 977, CHICO, CA 95927-0977
PO BOX 978, CHICO, CA 95927-0978
PO BOX 979, CHICO, CA 95927-0979
PO BOX 980, CHICO, CA 95927-0980
PO BOX 981, CHICO, CA 95927-0981
PO BOX 982, CHICO, CA 95927-0982
PO BOX 983, CHICO, CA 95927-0983
PO BOX 984, CHICO, CA 95927-0984
PO BOX 985, CHICO, CA 95927-0985
PO BOX 986, CHICO, CA 95927-0986
PO BOX 987, CHICO, CA 95927-0987
PO BOX 988, CHICO, CA 95927-0988
PO BOX 989, CHICO, CA 95927-0989
PO BOX 990, CHICO, CA 95927-0990
PO BOX 991, CHICO, CA 95927-0991
PO BOX 992, CHICO, CA 95927-0992
PO BOX 993, CHICO, CA 95927-0993
PO BOX 994, CHICO, CA 95927-0994
PO BOX 995, CHICO, CA 95927-0995
PO BOX 996, CHICO, CA 95927-0996
PO BOX 997, CHICO, CA 95927-0997
PO BOX 998, CHICO, CA 95927-0998
PO BOX 999, CHICO, CA 95927-0999
PO BOX 1000, CHICO, CA 95927-1000
PO BOX 1001, CHICO, CA 95927-1001
PO BOX 1002, CHICO, CA 95927-1002
PO BOX 1003, CHICO, CA 95927-1003
PO BOX 1004, CHICO, CA 95927-1004
PO BOX 1005, CHICO, CA 95927-1005
PO BOX 1006, CHICO, CA 95927-1006
PO BOX 1007, CHICO, CA 95927-1007
PO BOX 1008, CHICO, CA 95927-1008
PO BOX 1009, CHICO, CA 95927-1009
PO BOX 1010, CHICO, CA 95927-1010
PO BOX 1011, CHICO, CA 95927-1011
PO BOX 1012, CHICO, CA 95927-1012
PO BOX 1013, CHICO, CA 95927-1013
PO BOX 1014, CHICO, CA 95927-1014
PO BOX 1015, CHICO, CA 95927-1015
PO BOX 1016, CHICO, CA 95927-1016
PO BOX 1017, CHICO, CA 95927-1017
PO BOX 1018, CHICO, CA 95927-1018
PO BOX 1019, CHICO, CA 95927-1019
PO BOX 1020, CHICO, CA 95927-1020
PO BOX 1021, CHICO, CA 95927-1021
PO BOX 1022, CHICO, CA 95927-1022
PO BOX 1023, CHICO, CA 95927-1023
PO BOX 1024, CHICO, CA 95927-1024
PO BOX 1025, CHICO, CA 95927-1025
PO BOX 1026, CHICO, CA 95927-1026
PO BOX 1027, CHICO, CA 95927-1027
PO BOX 1028, CHICO, CA 95927-1028
PO BOX 1029, CHICO, CA 95927-1029
PO BOX 1030, CHICO, CA 95927-1030
PO BOX 1031, CHICO, CA 95927-1031
PO BOX 1032, CHICO, CA 95927-1032
PO BOX 1033, CHICO, CA 95927-1033
PO BOX 1034, CHICO, CA 95927-1034
PO BOX 1035, CHICO, CA 95927-1035
PO BOX 1036, CHICO, CA 95927-1036
PO BOX 1037, CHICO, CA 95927-1037
PO BOX 1038, CHICO, CA 95927-1038
PO BOX 1039, CHICO, CA 95927-1039
PO BOX 1040, CHICO, CA 95927-1040
PO BOX 1041, CHICO, CA 95927-1041
PO BOX 1042, CHICO, CA 95927-1042
PO BOX 1043, CHICO, CA 95927-1043
PO BOX 1044, CHICO, CA 95927-1044
PO BOX 1045, CHICO, CA 95927-1045
PO BOX 1046, CHICO, CA 95927-1046
PO BOX 1047, CHICO, CA 95927-1047
PO BOX 1048, CHICO, CA 95927-1048
PO BOX 1049, CHICO, CA 95927-1049
PO BOX 1050, CHICO, CA 95927-1050
PO BOX 1051, CHICO, CA 95927-1051
PO BOX 1052, CHICO, CA 95927-1052
PO BOX 1053, CHICO, CA 95927-1053
PO BOX 1054, CHICO, CA 95927-1054
PO BOX 1055, CHICO, CA 95927-1055
PO BOX 1056, CHICO, CA 95927-1056
PO BOX 1057, CHICO, CA 95927-1057
PO BOX 1058, CHICO, CA 95927-1058
PO BOX 1059, CHICO, CA 95927-1059
PO BOX 1060, CHICO, CA 95927-1060
PO BOX 1061, CHICO, CA 95927-1061
PO BOX 1062, CHICO, CA 95927-1062
PO BOX 1063, CHICO, CA 95927-1063
PO BOX 1064, CHICO, CA 95927-1064
PO BOX 1065, CHICO, CA 95927-1065
PO BOX 1066, CHICO, CA 95927-1066
PO BOX 1067, CHICO, CA 95927-1067
PO BOX 1068, CHICO, CA 95927-1068
PO BOX 1069, CHICO, CA 95927-1069
PO BOX 1070, CHICO, CA 95927-1070
PO BOX 1071, CHICO, CA 95927-1071
PO BOX 1072, CHICO, CA 95927-1072
PO BOX 1073, CHICO, CA 95927-1073
PO BOX 1074, CHICO, CA 95927-1074
PO BOX 1075, CHICO, CA 95927-1075
PO BOX 1076, CHICO, CA 95927-1076
PO BOX 1077, CHICO, CA 95927-1077
PO BOX 1078, CHICO, CA 95927-1078
PO BOX 1079, CHICO, CA 95927-1079
PO BOX 1080, CHICO, CA 95927-1080
PO BOX 1081, CHICO, CA 95927-1081
PO BOX 1082, CHICO, CA 95927-1082
PO BOX 1083, CHICO, CA 95927-1083
PO BOX 1084, CHICO, CA 95927-1084
PO BOX 1085, CHICO, CA 95927-1085
PO BOX 1086, CHICO, CA 95927-1086
PO BOX 1087, CHICO, CA 95927-1087
PO BOX 1088, CHICO, CA 95927-1088
PO BOX 1089, CHICO, CA 95927-1089
PO BOX 1090, CHICO, CA 95927-1090
PO BOX 1091, CHICO, CA 95927-1091
PO BOX 1092, CHICO, CA 95927-1092
PO BOX 1093, CHICO, CA 95927-1093
PO BOX 1094, CHICO, CA 95927-1094
PO BOX 1095, CHICO, CA 95927-1095
PO BOX 1096, CHICO, CA 95927-1096
PO BOX 1097, CHICO, CA 95927-1097
PO BOX 1098, CHICO, CA 95927-1098
PO BOX 1099, CHICO, CA 95927-1099
PO BOX 1100, CHICO, CA 95927-1100
PO BOX 1101, CHICO, CA 95927-1101
PO BOX 1102, CHICO, CA 95927-1102
PO BOX 1103, CHICO, CA 95927-1103
PO BOX 1104, CHICO, CA 95927-1104
PO BOX 1105, CHICO, CA 95927-1105
PO BOX 1106, CHICO, CA 95927-1106
PO BOX 1107, CHICO, CA 95927-1107
PO BOX 1108, CHICO, CA 95927-1108
PO BOX 1109, CHICO, CA 95927-1109
PO BOX 1110, CHICO, CA 95927-1110
PO BOX 1111, CHICO, CA 95927-1111
PO BOX 1112, CHICO, CA 95927-1112
PO BOX 1113, CHICO, CA 95927-1113
PO BOX 1114, CHICO, CA 95927-1114
PO BOX 1115, CHICO, CA 95927-1115
PO BOX 1116, CHICO, CA 95927-1116
PO BOX 1117, CHICO, CA 95927-1117
PO BOX 1118, CHICO, CA 95927-1118
PO BOX 1119, CHICO, CA 95927-1119
PO BOX 1120, CHICO, CA 95927-1120
PO BOX 1121, CHICO, CA 95927-1121
PO BOX 1122, CHICO, CA 95927-1122
PO BOX 1123, CHICO, CA 95927-1123
PO BOX 1124, CHICO, CA 95927-1124
PO BOX 1125, CHICO, CA 95927-1125
PO BOX 1126, CHICO, CA 95927-1126
PO BOX 1127, CHICO, CA 95927-1127
PO BOX 1128, CHICO, CA 95927-1128
PO BOX 1129, CHICO, CA 95927-1129
PO BOX 1130, CHICO, CA 95927-1130
PO BOX 1131, CHICO, CA 95927-1131
PO BOX 1132, CHICO, CA 95927-1132
PO BOX 1133, CHICO, CA 95927-1133