Every ZIP code in the United States, with weather, radar, trivia and the numbers behind it. Five digits since 1963!

ZIP stands for Zone Improvement Plan. The codes went live on July 1, 1963.The lowest ZIP code is 00501 — the IRS in Holtsville, New York.The highest ZIP code is 99950, in Ketchikan, Alaska.Type 07734 into a calculator and turn it upside down: hELLO. It is Keansburg, New Jersey.12345 belongs to one company: General Electric in Schenectady, New York.The first digit is a region: 0 is New England and New Jersey, 9 is the West Coast, Alaska and Hawaii.Mr. ZIP, the cartoon mailman, was the mascot that sold the idea to America.ZIP+4 arrived in 1983 and can narrow a ZIP down to one side of one block.A ZIP code is a mail route, not a place: plenty of them cross county and even state lines.Play ZIP Hunt: guess the secret ZIP code of the day in six tries.
zipcodes.pro — PREFIX/421

ZIP codes starting with 421

ZIP codes
33
States
KY
Largest city
Bowling Green, KY
Population
250,436

The first three digits of a ZIP code identify a sectional center facility — the postal processing plant that sorts mail for the area. It is a mail-routing grouping, not an administrative boundary.

Every ZIP code in 421xx

ZIP codes starting with 421
ZIP City Type Population Median income Median home
42101 Bowling Green , KY Standard 65,421 $48,217 $207,200
42102 Bowling Green , KY No street area — — —
42103 Bowling Green , KY Standard 21,911 $87,689 $331,400
42104 Bowling Green , KY Standard 42,076 $75,164 $306,400
42120 Adolphus , KY Standard 2,745 $64,958 $178,500
42122 Alvaton , KY Standard 5,513 $113,705 $297,100
42123 Austin , KY Standard 1,149 $61,010 —
42124 Beaumont , KY Standard 28 — —
42127 Cave City , KY Standard 7,030 $42,893 $164,000
42128 Drake , KY No street area — — —
42129 Edmonton , KY Standard 7,302 $53,609 $111,300
42130 Eighty Eight , KY Standard 124 — $222,300
42131 Etoile , KY Standard 72 — —
42133 Fountain Run , KY Standard 1,456 $62,353 $163,900
42134 Franklin , KY Standard 19,380 $59,113 $226,800
42135 Franklin , KY No street area — — —
42140 Gamaliel , KY Standard 1,367 $46,813 $91,900
42141 Glasgow , KY Standard 31,506 $52,896 $184,700
42142 Glasgow , KY No street area — — —
42151 Hestand , KY Standard 201 $108,056 $165,300
42152 Hiseville , KY No street area — — —
42153 Holland , KY Standard 18 — —
42154 Knob Lick , KY Standard 629 $58,036 $155,600
42156 Lucas , KY Standard 235 $98,000 $211,900
42157 Mount Hermon , KY Standard 507 $101,250 $175,000
42159 Oakland , KY Standard 1,699 $66,756 $264,400
42160 Park City , KY Standard 2,822 $49,364 $157,000
42163 Rocky Hill , KY Standard 48 — —
42164 Scottsville , KY Standard 17,673 $60,106 $196,800
42166 Summer Shade , KY Standard 2,691 $49,783 $116,200
42167 Tompkinsville , KY Standard 8,172 $48,497 $114,200
42170 Woodburn , KY Standard 1,938 $96,111 $291,700
42171 Smiths Grove , KY Standard 6,723 $70,191 $187,500

Cite this page

zipcodes.pro. “ZIP codes starting with 421.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/prefix/421

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