First three digits · Washington
ZIP Codes Starting with
67 ZIP codes start with 991, sorted at the Spokane, WA (SCF 990) sectional center (USPS labeling list L005, effective October 1, 2026) in Washington: 64 residential ZIP codes across 9 counties and 3 PO Box or single-organization codes (Census 2020 ZCTAs and GeoNames postal codes, October 2026).
What do the digits 991 mean?
The first digit, 9, is one of ten national areas (Alaska, California, Hawaii, Oregon, Washington, American Samoa, Guam, Northern Mariana Islands, Marshall Islands, Micronesia, Palau and Armed Forces Pacific). The first three, 991, route mail to a sectional center: USPS labeling list L005 (effective October 1, 2026) sends letters for 991 to the Spokane, WA (SCF 990) facility. The last two digits pick the delivery area. By residents, the largest town names among the 991 ZIP codes are Pullman, Colville, Newport, Kettle Falls, Chewelah and Davenport.
The same facility sorts 7 prefixes, 258 ZIP codes in all: 835, 838, 990, 991, 992, 993, 994.
Where are the 991 ZIP codes?
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries; ACS 2020-2024 5-year estimates (B19013).
All ZIP codes starting with 991
| County | ||||||
|---|---|---|---|---|---|---|
| 99101 | Addy | Stevens County | 1,690 | 18 | $79k | $435k |
| 99102 | Albion | Whitman County | 495 | 1,452 | $57k | $231k |
| 99103 | Almira | Lincoln County | 556 | 2 | $53k | $231k |
| 99104 | Belmont | Whitman County | PO Box or unique | – | – | – |
| 99105 | Benge | Adams County | 41 | 0 | $51k | $47k |
| 99107 | Boyds | Ferry County | PO Box or unique | – | – | – |
| 99109 | Chewelah | Stevens County | 4,981 | 16 | $62k | $327k |
| 99110 | Clayton | Stevens County | 1,505 | 39 | $76k | $453k |
| 99111 | Colfax | Whitman County | 4,038 | 13 | $73k | $296k |
| 99113 | Colton | Whitman County | 560 | 6 | $105k | $398k |
| 99114 | Colville | Stevens County | 13,383 | 19 | $63k | $302k |
| 99115 | Coulee City | Douglas County | 1,369 | 3 | $63k | $247k |
| 99116 | Coulee Dam | Okanogan County | 1,786 | 38 | $66k | $239k |
| 99117 | Creston | Lincoln County | 556 | 3 | $64k | $266k |
| 99118 | Curlew | Ferry County | 899 | 4 | $69k | $324k |
| 99119 | Cusick | Pend Oreille County | 1,549 | 4 | $95k | $360k |
| 99121 | Danville | Ferry County | 262 | 5 | – | $392k |
| 99122 | Davenport | Lincoln County | 4,046 | 7 | $82k | $332k |
| 99123 | Electric City | Grant County | 977 | 49 | $88k | $246k |
| 99124 | Elmer City | Okanogan County | 326 | 934 | $70k | $202k |
| 99125 | Endicott | Whitman County | 611 | 3 | $53k | $196k |
| 99126 | Evans | Stevens County | 899 | 18 | – | $366k |
| 99128 | Farmington | Whitman County | 259 | 4 | $59k | $364k |
| 99129 | Fruitland | Stevens County | 725 | 5 | $41k | $220k |
| 99130 | Garfield | Whitman County | 693 | 9 | $82k | $232k |
| 99131 | Gifford | Stevens County | 127 | 7 | $35k | $246k |
| 99133 | Grand Coulee | Douglas County | 1,115 | 6 | $69k | $230k |
| 99134 | Harrington | Lincoln County | 595 | 4 | $42k | $285k |
| 99135 | Hartline | Grant County | 395 | 2 | $81k | – |
| 99136 | Hay | Whitman County | 14 | 1 | $88k | – |
| 99137 | Hunters | Stevens County | 495 | 5 | $51k | $337k |
| 99138 | Inchelium | Ferry County | 1,223 | 2 | $51k | $218k |
| 99139 | Ione | Pend Oreille County | 1,091 | 3 | $52k | $274k |
| 99140 | Keller | Ferry County | 486 | 1 | $54k | $141k |
| 99141 | Kettle Falls | Ferry County | 5,626 | 9 | $58k | $321k |
| 99143 | Lacrosse | Whitman County | 585 | 2 | $38k | $124k |
| 99144 | Lamona | Lincoln County | 7 | 0 | – | – |
| 99146 | Laurier | Ferry County | 28 | 1 | – | – |
| 99147 | Lincoln | Lincoln County | 214 | 24 | $84k | $437k |
| 99148 | Loon Lake | Stevens County | 2,794 | 40 | $67k | $430k |
| 99149 | Malden | Whitman County | 100 | 52 | $26k | $50k |
| 99150 | Malo | Ferry County | 351 | 11 | $62k | $332k |
| 99151 | Marcus | Stevens County | 242 | 1,322 | $56k | $169k |
| 99152 | Metaline | Pend Oreille County | 157 | 36 | $66k | $233k |
| 99153 | Metaline Falls | Pend Oreille County | 467 | 2 | $44k | $282k |
| 99154 | Mohler | Lincoln County | 14 | 1 | – | – |
| 99155 | Nespelem | Okanogan County | 1,009 | 3 | $51k | $143k |
| 99156 | Newport | Pend Oreille County | 9,195 | 34 | $65k | $378k |
| 99157 | Northport | Stevens County | 605 | 9 | $44k | $233k |
| 99158 | Oakesdale | Whitman County | 561 | 6 | $78k | $302k |
| 99159 | Odessa | Lincoln County | 1,323 | 3 | $65k | $241k |
| 99160 | Orient | Ferry County | 87 | 2 | – | <$10k |
| 99161 | Palouse | Whitman County | 1,435 | 19 | $88k | $303k |
| 99163 | Pullman | Whitman County | 34,022 | 161 | $48k | $436k |
| 99164 | Pullman | Whitman County | PO Box or unique | – | – | – |
| 99166 | Republic | Ferry County | 2,953 | 6 | $57k | $286k |
| 99167 | Rice | Stevens County | 871 | 13 | $70k | $285k |
| 99169 | Ritzville | Adams County | 2,587 | 4 | $66k | $228k |
| 99170 | Rosalia | Whitman County | 926 | 5 | $59k | $238k |
| 99171 | Saint John | Whitman County | 895 | 4 | $53k | $221k |
| 99173 | Springdale | Stevens County | 1,623 | 11 | $60k | $282k |
| 99174 | Steptoe | Whitman County | 69 | 2,556 | $50k | $255k |
| 99176 | Thornton | Whitman County | 163 | 3 | $128k | $283k |
| 99179 | Uniontown | Whitman County | 645 | 10 | $79k | $398k |
| 99180 | Usk | Pend Oreille County | 465 | 3 | $64k | $429k |
| 99181 | Valley | Stevens County | 1,995 | 22 | $64k | $268k |
| 99185 | Wilbur | Lincoln County | 1,501 | 5 | $73k | $248k |
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; GeoNames postal codes (CC BY 4.0) for codes without a residential area.