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/DE/HIGHEST-DENSITY

Most Densely Populated ZIP Codes in Delaware

What this measures. People per square mile of land area. Source: Census American Community Survey and Gazetteer, data release 2026-10-12.

# ZIP City County People per sq mi
1 19717 Newark New Castle 23,395
2 19805 Wilmington New Castle 7,503
3 19802 Wilmington New Castle 7,477
4 19806 Wilmington New Castle 5,734
5 19703 Claymont New Castle 3,893
6 19801 Wilmington New Castle 3,713
7 19955 Kenton Kent 3,556
8 19810 Wilmington New Castle 3,360
9 19808 Wilmington New Castle 2,842
10 19804 Wilmington New Castle 2,617
11 19713 Newark New Castle 2,365
12 19809 Wilmington New Castle 2,118
13 19702 Newark New Castle 1,982
14 19711 Newark New Castle 1,804
15 19803 Wilmington New Castle 1,760
16 19733 Saint Georges New Castle 1,691
17 19720 New Castle New Castle 1,629
18 19701 Bear New Castle 1,618
19 19967 Millville Sussex 1,464
20 19707 Hockessin New Castle 1,318
21 19980 Woodside Kent 1,150
22 19962 Magnolia Kent 942
23 19970 Ocean View Sussex 914
24 19904 Dover Kent 899
25 19736 Yorklyn New Castle 841
26 19971 Rehoboth Beach Sussex 829
27 19706 Delaware City New Castle 805
28 19936 Cheswold Kent 738
29 19709 Middletown New Castle 686
30 19958 Lewes Sussex 676
31 19730 Odessa New Castle 630
32 19930 Bethany Beach Sussex 515
33 19944 Fenwick Island Sussex 512
34 19901 Dover Kent 498
35 19807 Wilmington New Castle 430
36 19975 Selbyville Sussex 425
37 19966 Millsboro Sussex 403
38 19977 Smyrna Kent 333
39 19973 Seaford Sussex 320
40 19931 Bethel Sussex 314
41 19934 Camden Wyoming Kent 302
42 19939 Dagsboro Sussex 288
43 19731 Port Penn New Castle 259
44 19951 Harbeson Sussex 251
45 19946 Frederica Kent 243
46 19968 Milton Sussex 242
47 19960 Lincoln Sussex 224
48 19963 Milford Sussex 224
49 19943 Felton Kent 215
50 19938 Clayton Kent 198

Showing the top 50 of 68 ZIP codes in Delaware that have this figure . 19717 ranks 1st at 23,395, against 198 in 50th place.

Other rankings for Delaware

Cite this page

zipcodes.pro. “Most Densely Populated ZIP Codes in Delaware.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/rankings/de/highest-density

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