First three digits · Missouri
ZIP Codes Starting with
51 ZIP codes start with 633, sorted at the St Louis, MO (SCF 630) sectional center (USPS labeling list L005, effective October 1, 2026) in Missouri: 45 residential ZIP codes across 7 counties and 6 PO Box or single-organization codes (Census 2020 ZCTAs and GeoNames postal codes, October 2026).
What do the digits 633 mean?
The first digit, 6, is one of ten national areas (Illinois, Kansas, Missouri and Nebraska). The first three, 633, route mail to a sectional center: USPS labeling list L005 (effective October 1, 2026) sends letters for 633 to the St Louis, MO (SCF 630) facility. The last two digits pick the delivery area. By residents, the largest town names among the 633 ZIP codes are Saint Charles, O Fallon, Saint Peters, Wentzville, Lake Saint Louis and Troy.
The same facility sorts 12 prefixes, 714 ZIP codes in all: 620, 622, 628, 629, 630, 631, 633, 634, 636, 637, 638, 639.
Where are the 633 ZIP codes?
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries; ACS 2020-2024 5-year estimates (B19013).
All ZIP codes starting with 633
| County | ||||||
|---|---|---|---|---|---|---|
| 63301 | Saint Charles | St. Charles County | 52,667 | 625 | $85k | $268k |
| 63302 | Saint Charles | St. Charles County | PO Box or unique | – | – | – |
| 63303 | Saint Charles | St. Charles County | 46,089 | 2,333 | $99k | $321k |
| 63304 | Saint Charles | St. Charles County | 43,195 | 784 | $114k | $351k |
| 63330 | Annada | Pike County | 108 | 5 | $58k | – |
| 63332 | Augusta | St. Charles County | 1,651 | 29 | $146k | $385k |
| 63333 | Bellflower | Montgomery County | 688 | 14 | $65k | $166k |
| 63334 | Bowling Green | Pike County | 7,564 | 46 | $55k | $160k |
| 63336 | Clarksville | Pike County | 1,079 | 14 | $72k | $163k |
| 63338 | Cottleville | St. Charles County | PO Box or unique | – | – | – |
| 63339 | Curryville | Pike County | 996 | 14 | $82k | $209k |
| 63341 | Defiance | St. Charles County | 3,515 | 91 | $171k | $607k |
| 63342 | Dutzow | Warren County | PO Box or unique | – | – | – |
| 63343 | Elsberry | Lincoln County | 4,381 | 39 | $75k | $169k |
| 63344 | Eolia | Pike County | 1,501 | 18 | $69k | $186k |
| 63345 | Farber | Audrain County | 291 | 15 | $44k | $80k |
| 63346 | Flinthill | St. Charles County | PO Box or unique | – | – | – |
| 63347 | Foley | Lincoln County | 3,140 | 86 | $82k | $172k |
| 63348 | Foristell | St. Charles County | 10,394 | 186 | $116k | $386k |
| 63349 | Hawk Point | Lincoln County | 2,149 | 65 | $80k | $250k |
| 63350 | High Hill | Montgomery County | 769 | 33 | $69k | – |
| 63351 | Jonesburg | Warren County | 1,389 | 25 | $68k | $207k |
| 63352 | Laddonia | Audrain County | 1,018 | 10 | $55k | $98k |
| 63353 | Louisiana | Pike County | 4,790 | 57 | $47k | $96k |
| 63357 | Marthasville | Warren County | 6,536 | 53 | $92k | $293k |
| 63359 | Middletown | Pike County | 1,667 | 11 | $75k | $160k |
| 63361 | Montgomery City | Montgomery County | 4,460 | 28 | $62k | $187k |
| 63362 | Moscow Mills | Lincoln County | 9,930 | 261 | $89k | $236k |
| 63363 | New Florence | Montgomery County | 949 | 11 | $47k | $98k |
| 63365 | New Melle | St. Charles County | 51 | 155 | $54k | – |
| 63366 | O Fallon | St. Charles County | 54,769 | 790 | $101k | $305k |
| 63367 | Lake Saint Louis | St. Charles County | 29,725 | 2,295 | $138k | $409k |
| 63368 | O Fallon | St. Charles County | 46,966 | 2,896 | $124k | $349k |
| 63369 | Old Monroe | Lincoln County | 2,822 | 99 | $96k | $339k |
| 63370 | Olney | Lincoln County | PO Box or unique | – | – | – |
| 63373 | Portage Des Sioux | St. Charles County | 690 | 37 | $89k | $221k |
| 63376 | Saint Peters | St. Charles County | 74,962 | 1,868 | $96k | $275k |
| 63377 | Silex | Lincoln County | 3,501 | 27 | $88k | $234k |
| 63378 | Treloar | Warren County | PO Box or unique | – | – | – |
| 63379 | Troy | Lincoln County | 27,731 | 204 | $91k | $257k |
| 63380 | Truesdale | Warren County | 990 | 800 | $59k | $214k |
| 63381 | Truxton | Warren County | 618 | 22 | $112k | $237k |
| 63382 | Vandalia | Audrain County | 4,033 | 32 | $61k | $96k |
| 63383 | Warrenton | Warren County | 16,927 | 106 | $75k | $243k |
| 63384 | Wellsville | Montgomery County | 2,049 | 25 | $78k | $129k |
| 63385 | Wentzville | St. Charles County | 51,330 | 768 | $112k | $347k |
| 63386 | West Alton | St. Charles County | 482 | 15 | $110k | $157k |
| 63387 | Whiteside | Lincoln County | 108 | 1,174 | $104k | $97k |
| 63388 | Williamsburg | Callaway County | 685 | 11 | $72k | $66k |
| 63389 | Winfield | Lincoln County | 7,616 | 172 | $98k | $237k |
| 63390 | Wright City | Warren County | 10,970 | 140 | $82k | $268k |
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; GeoNames postal codes (CC BY 4.0) for codes without a residential area.