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 — RANKINGS/WA/MOST-TAX-RETURNS

ZIP Codes With the Most Tax Returns Filed in Washington

What this measures. Number of individual income tax returns filed. A rough proxy for how many households a ZIP code contains, available where census figures are not. Source: IRS Statistics of Income, ZIP code data, data release 2026-10-12.

# ZIP City County Returns filed
1 99301 Pasco Franklin 37,870
2 98052 Redmond King 37,180
3 98012 Bothell Snohomish 33,570
4 98682 Vancouver Clark 32,560
5 98103 Seattle King 30,420
6 98115 Seattle King 29,540
7 98391 Bonney Lake Pierce 27,990
8 98208 Everett Snohomish 27,720
9 99208 Spokane Spokane 27,080
10 98034 Kirkland King 26,550
11 98270 Marysville Snohomish 25,630
12 98133 Seattle King 25,500
13 98258 Lake Stevens Snohomish 25,020
14 98118 Seattle King 24,860
15 98023 Federal Way King 24,210
16 98042 Kent King 24,150
17 98122 Seattle King 23,860
18 98387 Spanaway Pierce 23,820
19 98092 Auburn King 23,170
20 98226 Bellingham Whatcom 22,930
21 98632 Longview Cowlitz 22,790
22 98225 Bellingham Whatcom 22,680
23 98003 Federal Way King 22,640
24 98374 Puyallup Pierce 22,440
25 98501 Olympia Thurston 22,400
26 98661 Vancouver Clark 22,200
27 99336 Kennewick Benton 22,000
28 98223 Arlington Snohomish 21,890
29 98125 Seattle King 21,720
30 98058 Renton King 21,480
31 98109 Seattle King 21,450
32 98801 Wenatchee Chelan 21,250
33 99205 Spokane Spokane 20,880
34 98033 Kirkland King 20,590
35 98031 Kent King 20,540
36 98837 Moses Lake Grant 20,380
37 98036 Lynnwood Snohomish 20,240
38 98087 Lynnwood Snohomish 20,130
39 98004 Bellevue King 20,120
40 98204 Everett Snohomish 19,910
41 98902 Yakima Yakima 19,860
42 98059 Renton King 19,540
43 98503 Lacey Thurston 19,460
44 98006 Bellevue King 19,420
45 98026 Edmonds Snohomish 19,410
46 98277 Oak Harbor Island 19,010
47 98198 Seattle King 18,780
48 98117 Seattle King 18,740
49 98604 Battle Ground Clark 18,640
50 98908 Yakima Yakima 18,640

Showing the top 50 of 498 ZIP codes in Washington that have this figure . 99301 ranks 1st at 37,870, against 18,640 in 50th place.

Other rankings for Washington

Cite this page

zipcodes.pro. “ZIP Codes With the Most Tax Returns Filed in Washington.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/rankings/wa/most-tax-returns

Underlying data is public domain or openly licensed — sources, vintages and licences.