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 21, RAMONA, CA 92065-0021
PO BOX 22, RAMONA, CA 92065-0022
PO BOX 23, RAMONA, CA 92065-0023
PO BOX 24, RAMONA, CA 92065-0024
PO BOX 25, RAMONA, CA 92065-0025
PO BOX 26, RAMONA, CA 92065-0026
PO BOX 27, RAMONA, CA 92065-0027
PO BOX 28, RAMONA, CA 92065-0028
PO BOX 29, RAMONA, CA 92065-0029
PO BOX 30, RAMONA, CA 92065-0030
PO BOX 31, RAMONA, CA 92065-0031
PO BOX 32, RAMONA, CA 92065-0032
PO BOX 33, RAMONA, CA 92065-0033
PO BOX 34, RAMONA, CA 92065-0034
PO BOX 35, RAMONA, CA 92065-0035
PO BOX 36, RAMONA, CA 92065-0036
PO BOX 37, RAMONA, CA 92065-0037
PO BOX 38, RAMONA, CA 92065-0038
PO BOX 39, RAMONA, CA 92065-0039
PO BOX 40, RAMONA, CA 92065-0040
PO BOX 41, RAMONA, CA 92065-0041
PO BOX 42, RAMONA, CA 92065-0042
PO BOX 43, RAMONA, CA 92065-0043
PO BOX 44, RAMONA, CA 92065-0044
PO BOX 45, RAMONA, CA 92065-0045
PO BOX 46, RAMONA, CA 92065-0046
PO BOX 47, RAMONA, CA 92065-0047
PO BOX 48, RAMONA, CA 92065-0048
PO BOX 49, RAMONA, CA 92065-0049
PO BOX 50, RAMONA, CA 92065-0050
PO BOX 51, RAMONA, CA 92065-0051
PO BOX 52, RAMONA, CA 92065-0052
PO BOX 53, RAMONA, CA 92065-0053
PO BOX 54, RAMONA, CA 92065-0054
PO BOX 55, RAMONA, CA 92065-0055
PO BOX 56, RAMONA, CA 92065-0056
PO BOX 57, RAMONA, CA 92065-0057
PO BOX 58, RAMONA, CA 92065-0058
PO BOX 59, RAMONA, CA 92065-0059
PO BOX 60, RAMONA, CA 92065-0060
PO BOX 61, RAMONA, CA 92065-0061
PO BOX 62, RAMONA, CA 92065-0062
PO BOX 63, RAMONA, CA 92065-0063
PO BOX 64, RAMONA, CA 92065-0064
PO BOX 65, RAMONA, CA 92065-0065
PO BOX 66, RAMONA, CA 92065-0066
PO BOX 67, RAMONA, CA 92065-0067
PO BOX 68, RAMONA, CA 92065-0068
PO BOX 69, RAMONA, CA 92065-0069
PO BOX 70, RAMONA, CA 92065-0070
PO BOX 71, RAMONA, CA 92065-0071
PO BOX 72, RAMONA, CA 92065-0072
PO BOX 73, RAMONA, CA 92065-0073
PO BOX 74, RAMONA, CA 92065-0074
PO BOX 75, RAMONA, CA 92065-0075
PO BOX 76, RAMONA, CA 92065-0076
PO BOX 77, RAMONA, CA 92065-0077
PO BOX 78, RAMONA, CA 92065-0078
PO BOX 79, RAMONA, CA 92065-0079
PO BOX 80, RAMONA, CA 92065-0080
PO BOX 81, RAMONA, CA 92065-0081
PO BOX 82, RAMONA, CA 92065-0082
PO BOX 83, RAMONA, CA 92065-0083
PO BOX 84, RAMONA, CA 92065-0084
PO BOX 85, RAMONA, CA 92065-0085
PO BOX 86, RAMONA, CA 92065-0086
PO BOX 87, RAMONA, CA 92065-0087
PO BOX 88, RAMONA, CA 92065-0088
PO BOX 89, RAMONA, CA 92065-0089
PO BOX 90, RAMONA, CA 92065-0090
PO BOX 91, RAMONA, CA 92065-0091
PO BOX 92, RAMONA, CA 92065-0092
PO BOX 93, RAMONA, CA 92065-0093
PO BOX 94, RAMONA, CA 92065-0094
PO BOX 95, RAMONA, CA 92065-0095
PO BOX 96, RAMONA, CA 92065-0096
PO BOX 97, RAMONA, CA 92065-0097
PO BOX 98, RAMONA, CA 92065-0098
PO BOX 99, RAMONA, CA 92065-0099
PO BOX 100, RAMONA, CA 92065-0100
PO BOX 101, RAMONA, CA 92065-0101
PO BOX 102, RAMONA, CA 92065-0102
PO BOX 103, RAMONA, CA 92065-0103
PO BOX 104, RAMONA, CA 92065-0104
PO BOX 105, RAMONA, CA 92065-0105
PO BOX 106, RAMONA, CA 92065-0106
PO BOX 107, RAMONA, CA 92065-0107
PO BOX 108, RAMONA, CA 92065-0108
PO BOX 109, RAMONA, CA 92065-0109
PO BOX 110, RAMONA, CA 92065-0110
PO BOX 111, RAMONA, CA 92065-0111
PO BOX 112, RAMONA, CA 92065-0112
PO BOX 113, RAMONA, CA 92065-0113
PO BOX 114, RAMONA, CA 92065-0114
PO BOX 115, RAMONA, CA 92065-0115
PO BOX 116, RAMONA, CA 92065-0116
PO BOX 117, RAMONA, CA 92065-0117
PO BOX 118, RAMONA, CA 92065-0118
PO BOX 119, RAMONA, CA 92065-0119
PO BOX 120, RAMONA, CA 92065-0120
PO BOX 121, RAMONA, CA 92065-0121
PO BOX 122, RAMONA, CA 92065-0122
PO BOX 123, RAMONA, CA 92065-0123
PO BOX 124, RAMONA, CA 92065-0124
PO BOX 125, RAMONA, CA 92065-0125
PO BOX 126, RAMONA, CA 92065-0126
PO BOX 127, RAMONA, CA 92065-0127
PO BOX 128, RAMONA, CA 92065-0128
PO BOX 129, RAMONA, CA 92065-0129
PO BOX 130, RAMONA, CA 92065-0130
PO BOX 131, RAMONA, CA 92065-0131
PO BOX 132, RAMONA, CA 92065-0132
PO BOX 133, RAMONA, CA 92065-0133
PO BOX 134, RAMONA, CA 92065-0134
PO BOX 135, RAMONA, CA 92065-0135
PO BOX 136, RAMONA, CA 92065-0136
PO BOX 137, RAMONA, CA 92065-0137
PO BOX 138, RAMONA, CA 92065-0138
PO BOX 139, RAMONA, CA 92065-0139
PO BOX 140, RAMONA, CA 92065-0140
PO BOX 141, RAMONA, CA 92065-0141
PO BOX 142, RAMONA, CA 92065-0142
PO BOX 143, RAMONA, CA 92065-0143
PO BOX 144, RAMONA, CA 92065-0144
PO BOX 145, RAMONA, CA 92065-0145
PO BOX 146, RAMONA, CA 92065-0146
PO BOX 147, RAMONA, CA 92065-0147
PO BOX 148, RAMONA, CA 92065-0148
PO BOX 149, RAMONA, CA 92065-0149
PO BOX 150, RAMONA, CA 92065-0150
PO BOX 151, RAMONA, CA 92065-0151
PO BOX 152, RAMONA, CA 92065-0152
PO BOX 153, RAMONA, CA 92065-0153
PO BOX 154, RAMONA, CA 92065-0154
PO BOX 155, RAMONA, CA 92065-0155
PO BOX 156, RAMONA, CA 92065-0156
PO BOX 157, RAMONA, CA 92065-0157
PO BOX 158, RAMONA, CA 92065-0158
PO BOX 159, RAMONA, CA 92065-0159
PO BOX 160, RAMONA, CA 92065-0160
PO BOX 161, RAMONA, CA 92065-0161
PO BOX 162, RAMONA, CA 92065-0162
PO BOX 163, RAMONA, CA 92065-0163
PO BOX 164, RAMONA, CA 92065-0164
PO BOX 165, RAMONA, CA 92065-0165
PO BOX 166, RAMONA, CA 92065-0166
PO BOX 167, RAMONA, CA 92065-0167
PO BOX 168, RAMONA, CA 92065-0168
PO BOX 169, RAMONA, CA 92065-0169
PO BOX 170, RAMONA, CA 92065-0170
PO BOX 171, RAMONA, CA 92065-0171
PO BOX 172, RAMONA, CA 92065-0172
PO BOX 173, RAMONA, CA 92065-0173
PO BOX 174, RAMONA, CA 92065-0174
PO BOX 175, RAMONA, CA 92065-0175
PO BOX 176, RAMONA, CA 92065-0176
PO BOX 177, RAMONA, CA 92065-0177
PO BOX 178, RAMONA, CA 92065-0178
PO BOX 179, RAMONA, CA 92065-0179
PO BOX 180, RAMONA, CA 92065-0180
PO BOX 181, RAMONA, CA 92065-0181
PO BOX 182, RAMONA, CA 92065-0182
PO BOX 183, RAMONA, CA 92065-0183
PO BOX 184, RAMONA, CA 92065-0184
PO BOX 185, RAMONA, CA 92065-0185
PO BOX 186, RAMONA, CA 92065-0186
PO BOX 187, RAMONA, CA 92065-0187
PO BOX 188, RAMONA, CA 92065-0188
PO BOX 189, RAMONA, CA 92065-0189
PO BOX 190, RAMONA, CA 92065-0190
PO BOX 191, RAMONA, CA 92065-0191
PO BOX 192, RAMONA, CA 92065-0192
PO BOX 193, RAMONA, CA 92065-0193
PO BOX 194, RAMONA, CA 92065-0194
PO BOX 195, RAMONA, CA 92065-0195
PO BOX 196, RAMONA, CA 92065-0196
PO BOX 197, RAMONA, CA 92065-0197
PO BOX 198, RAMONA, CA 92065-0198
PO BOX 199, RAMONA, CA 92065-0199
PO BOX 200, RAMONA, CA 92065-0200
PO BOX 201, RAMONA, CA 92065-0201
PO BOX 202, RAMONA, CA 92065-0202
PO BOX 203, RAMONA, CA 92065-0203
PO BOX 204, RAMONA, CA 92065-0204
PO BOX 205, RAMONA, CA 92065-0205
PO BOX 206, RAMONA, CA 92065-0206
PO BOX 207, RAMONA, CA 92065-0207
PO BOX 208, RAMONA, CA 92065-0208
PO BOX 209, RAMONA, CA 92065-0209
PO BOX 210, RAMONA, CA 92065-0210
PO BOX 211, RAMONA, CA 92065-0211
PO BOX 212, RAMONA, CA 92065-0212
PO BOX 213, RAMONA, CA 92065-0213
PO BOX 214, RAMONA, CA 92065-0214
PO BOX 215, RAMONA, CA 92065-0215
PO BOX 216, RAMONA, CA 92065-0216
PO BOX 217, RAMONA, CA 92065-0217
PO BOX 218, RAMONA, CA 92065-0218
PO BOX 219, RAMONA, CA 92065-0219
PO BOX 220, RAMONA, CA 92065-0220
PO BOX 221, RAMONA, CA 92065-0221