County Maps US

Sussex County, Delaware

The largest of Delaware's 3 counties by land area.

CountyFIPS 10005

Within Delaware
Sussex County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data. The dot marks Georgetown, the county seat, located via the 2025 Census Gazetteer.

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Population
277,140
+38,513 (+16.1%) since 2020
Land area
936.1
square miles. A further 21.8% of the total area is water
Population density
296
people per square mile, computed rather than published
County seat
Georgetown
Seat of county government.
Established
1683
342 years ago
Largest city
Seaford city
Population 9,165.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of Sussex County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of Sussex County, Delaware from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 800 by 780 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where Sussex County ranks

Position among the 3 counties of Delaware, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn DelawareNationally
Population277,1402nd of 3268th of 3,144
Land area936.1 sq mi1st of 3762nd of 3,144
Population density296 per sq mi3rd of 3444th of 3,144
Median household income$81,4972nd of 3524th of 3,143

Full data for Sussex County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population277,140Vintage 2025 Population Estimates
Population in 2020238,627Vintage 2025 Population Estimates
2020 estimates base?237,379Vintage 2025 Population Estimates
Land area936.1 sq mi2025 Gazetteer Files
Water area260.3 sq mi2025 Gazetteer Files
Total area1,196 sq mi2025 Gazetteer Files
Population density?296 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$81,497American Community Survey 2020-2024 5-Year Estimates
Median home value$382,600American Community Survey 2020-2024 5-Year Estimates
Median age51.9American Community Survey 2020-2024 5-Year Estimates
Households106,441American Community Survey 2020-2024 5-Year Estimates
Housing units151,799American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
-1,011
2,404 births, 3,415 deaths
Net migration
+6,926
More people moved in than moved out.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 6 areas bordering Sussex County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Kent CountyDelaware43 mi194,786
Wicomico CountyMaryland26 mi106,899
Worcester CountyMaryland19 mi54,459
Cape May CountyNew Jersey16 mi93,390
Caroline CountyMaryland13 mi34,116
Dorchester CountyMaryland5.2 mi33,628

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

All 3 counties of Delaware

Open the interactive Delaware county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.