Delaware County Map With Cities
By Marko Visic · Updated Oct 5, 2026
Delaware has 3 counties, covering 1,949 square miles of land. The Census Bureau estimates its population at 1,059,952 as of July 1, 2025. The largest county by land area is Sussex County; the most populous is New Castle County; the least populous is Kent County.
Tap or click any county for details. Need a printable version? Blank Delaware map (PDF/PNG/SVG).
All 3 Delaware counties
| County | FIPS code | Population (July 1, 2025) ▼ | Change since April 2020 | Land area (sq mi) | People per sq mi | Median household income (2020–2024) |
|---|---|---|---|---|---|---|
| New Castle County | 10003 | 588,026 | +3.0% | 426 | 1,379 | $91,166 |
| Sussex County | 10005 | 277,140 | +16.8% | 936 | 296 | $81,497 |
| Kent County | 10001 | 194,786 | +7.1% | 586 | 332 | $74,477 |
FIPS code: the Census Bureau’s five-digit county ID, a two-digit state code plus a three-digit county code. It is not a ZIP code.
How many counties does Delaware have?
Delaware has 3 counties covering 1,949 square miles. The state was admitted to the Union in 1787 as the 1st state.
The largest county by land area is Sussex County at 936 square miles, home to 277,140 residents. The most populous is New Castle County with 588,026 residents — a density of 1,379 people per square mile. At the other end of the scale, Kent County has 194,786 residents.
Delaware’s capital is Dover, while the largest city is Wilmington.
Related resources
Download a printable outline of Delaware’s county boundaries from our blank map of Delaware page — available in SVG, PNG, and PDF.
Use the What County Am I In? tool to detect which Delaware county a GPS location or address falls in, or the Address to County Lookup for batch input.
For demographic radius analysis, the Find ZIP Codes in Radius and Population Within Radius tools let you draw a circle around any Delaware address and see every ZIP code and the total population inside.
Two SimpleMapLab studies cover Delaware specifically: the 100-mile radius around Dover measures how much of the state lives within 100 miles of its capitol, and the loneliest town in Delaware ranks the state’s most isolated inhabited place. The county-counts blog post puts Delaware’s 3 counties in national context.
Frequently asked questions
- County Population Totals, Vintage 2025: estimates for July 1, 2025, released March 2026
- Gazetteer Files, 2026: county land and water area
- American Community Survey 5-Year Estimates, 2020–2024: median household income (table B19013)
- County boundaries on the map: US Atlas TopoJSON build of the US Census Bureau’s TIGER/Line shapefiles. All figures are US Census Bureau data in the public domain.