Delaware county populations
3 supported county-equivalent records in Delaware; July 1, 2025 population, 2024–2025 growth and 2025 land-area density.
Population totals use July 1, 2025 observations from PEP Vintage 2025. Change is measured since July 1, 2024. County equivalents are included, including Connecticut planning regions. Missing density is displayed as unavailable, never as zero.
Population table and filters
Whole-dataset downloads| Place | Population · 2025 | Change · 2024–25 | Growth · 2024–25 | People / sq. mi. |
|---|---|---|---|---|
| New Castle CountyDelaware · County equivalent · 10003 | 588,026 | +2,012 | +0.34% | 1,379.2 |
| Sussex CountyDelaware · County equivalent · 10005 | 277,140 | +5,907 | +2.18% | 296.0 |
| Kent CountyDelaware · County equivalent · 10001 | 194,786 | +1,910 | +0.99% | 332.4 |
Use these comparisons consistently
A larger population does not necessarily mean faster growth. Absolute change measures the number of residents gained or lost; percentage change divides that difference by the starting population. The percentage column here covers one July-to-July interval, rather than a decade or a partial calendar year. Percent growth is suppressed where the starting population is zero.
Density divides the unrounded July 1, 2025 population by matching 2025 Gazetteer land area. It is measured in people per square mile and excludes water area. These geographic averages depend on the size and definition of each unit, so a county’s density is not directly comparable to a built-up city neighborhood.
County-equivalent names and units vary by state. Connecticut planning regions are represented in the current series; linking older county series requires a documented relationship. Incorporated places may cross county boundaries and do not form an exhaustive county breakdown.
Exports contain the current page’s visible rows after filtering, with reference date and release metadata. Use whole-dataset downloads for every row or select a compatible comparison to inspect a longer interval. The initial pep-2025-r1 snapshot remains reproducible when future releases are added.