How many people live in New Castle County, DE?
Updated Apr. 6, 2026Refreshed annually
In 2024, there were about 588,100 people living in New Castle County, DE. That makes New Castle County the most populous county in Delaware. It is home to 55.5% of people living in the state.
588K
population of New Castle County, DE (2024)
55.5%
County share of the Delaware population (2024)
About 588,100 people lived in New Castle County, DE in 2024.
Population estimates, 2000–2024
What are New Castle County, DE’s age demographics?
About 105,800 New Castle County, DE residents are aged 65 and older in 2024. That represents 18% of its population. For comparison, the age group represents 21.8% of Delaware’s population and 18% in the US overall.
Another 122,600 New Castle County residents, or 20.9% of the population, were children under 18. For comparison, the age group represents 20.4% of Delaware’s population and 21.6% in the US overall.
A lower share of New Castle County, DE's population is aged under 18 than the US as a whole.
Population estimates by age group, (2024)
What are New Castle County, DE’s racial and ethnic demographics?
Non-Hispanic Black or African American residents make up 26.1% of the New Castle County population, higher than the national share of 12.6%. New Castle County also has a larger share of people identifying as non-Hispanic Asian (6.8%) than the US overall (6.5%).
In contrast, New Castle County’s Hispanic population accounts for 12.5%, below the 20% nationwide, and the non-Hispanic white population makes up 51.7% of the county, compared with 57.5% nationally.
Racial and ethnic make up differ based on location. These figures reflect how people identified their race alone (not in combination with other races), and separate out Hispanic or Latino ethnicity, following Census reporting standards.
New Castle County, DE has a higher share of a non-Hispanic Black or African American population than Delaware as a whole.
Population estimates by race and ethnicity, (2024)
The largest city or town in New Castle County, DE is Wilmington with about 73,200 residents in 2024.
Cities and towns in New Castle County, DE ranked by population
Population (2024), includes only portions within county
| City or town | Population | |
|---|---|---|
| 1. | Wilmington | 73,176 |
| 2. | Newark | 30,506 |
| 3. | Middletown | 25,686 |
| 4. | Elsmere | 6,234 |
| 5. | New Castle | 5,715 |
| 6. | Townsend | 2,941 |
| 7. | Delaware City | 1,933 |
| 8. | Bellefonte | 1,249 |
| 9. | Newport | 909 |
| 10. | Arden | 437 |
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Methodology
USAFacts standardizes data, in areas such as time and demographics, to make it easier to understand and compare.
The analysis was generated with the help of AI and reviewed by USAFacts for accuracy.
Page sources
USAFacts endeavors to share the most up-to-date information available. We sourced the data on this page directly from government agencies; however, the intervals at which agencies publish updated data vary.
