Contents 1 Introduction. 1 11 Background . 1 111 Purpose . 1 112 Scope . 1 113 Additional Benefits . 1 12 Overview . 2 121 Address and List Maintenance . 2 122 List Correction. 2 123 Updates. 2 124 Address Output . 3 125 Deliverability . 3 13 Address Information Systems Products and Services . 3 2 Postal Addressing Standards . 5 21 General . 5 211 Standardized Delivery Address Line and Last Line. 5 212 Format . 5 213 Secondary Address Unit Designators . 6 214 Attention Line . 7 215 Dual Addresses . 7 22 Last Line of the Address. 8 221 City Names . 8 222 Punctuation . 8 223 Spelling of City Names . 8 224 Format . 9 225 Military Addresses. 9 226 Preprinted Delivery Point Barcodes . 9 23 Delivery Address Line . 10 231 Components . 10 232 Street Name . 10 233 Directionals . 11 234 Suffixes . 13 235 Numeric Street Names . 13 236 Corner Addresses . 14 237 Highways. 14 238 Military Addresses. 14 239 Department of State Addresses . 15 June 2020 i Postal Addressing Standards 24 Rural Route Addresses. 15 241 Format . 15 242 Leading Zero . 16 243 Hyphens . 16 244 Designations RFD and RD . 16 245 Additional Designations . 16 246 ZIP+4. 16 25 Highway Contract Route Addresses . 17 251 Format . 17 252 Leading Zero . 17 253 Hyphens . 17 254 Star Route Designations . 17 255 Additional Designations . 18 256 ZIP+4. 18 26 General Delivery Addresses . 18 261 Format . 18 262 ZIP Code or ZIP+4 . 18 27 United States Postal Service Addresses . 19 271 Format . 19 272 ZIP Code or ZIP+4 . 19 28 Post Office Box Addresses. 19 281 Format . 19 282 Leading Zero . 20 283 Designations . 20 284 PO Box Street Addressing . 20 285 Private Mailbox Addresses . ..