Cities in Delaware by population
Wilmington, DE had the highest population of 6 cities in 2021, at 70,833. Milford, DE had the lowest, at 12,331. The median was 27,035 and the figure for Delaware was 1.01 million. Source: the U.S. Census Bureau.
All cities, 2021
Full ranking
| Rank | Cities | 2021 | Change on 2020 |
|---|---|---|---|
| 1 | Wilmington, DE | 70,833 | -0.1% |
| 2 | Dover, DE | 39,746 | +0.8% |
| 3 | Newark, DE | 29,803 | -2.6% |
| 4 | Middletown, DE | 24,266 | +3.8% |
| 5 | Smyrna, DE | 13,168 | +1.6% |
| 6 | Milford, DE | 12,331 | +9.2% |
Other periods
About this ranking
Resident population. Spain and the EU: 1 January, with Spanish figures from the official municipal register (Padrón). Norway: Statistics Norway, 1 January. United States: Census Bureau population estimates for 1 July. United Kingdom regions and local authorities: Office for National Statistics estimates for 30 June. Other countries and the World: World Bank mid-year estimates, which count all residents regardless of legal status or citizenship.
The World Bank series exists for every country, so use it (through compare) to rank countries on one basis.
Every value in the ranking comes from the same publisher and the same period, so the cities are compared on one definition. Equal values share a rank.
How to cite
U.S. Census Bureau. Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-12.Citation styles
APA 7
U.S. Census Bureau. (2026). Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals) (Cities in Delaware by population, 2021) [Data set]. Retrieved October 12, 2026, from https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/
MLA 9
Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals), Cities in Delaware by population, 2021. U.S. Census Bureau, 14 May 2026, https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Invokely, https://invokely.ai/rankings/population/delaware-cities?period=2021. Accessed 12 Oct. 2026.
Chicago (author-date)
U.S. Census Bureau. 2026. Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals). Cities in Delaware by population, 2021. Dataset. Accessed October 12, 2026. https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Also distributed by Invokely, https://invokely.ai/rankings/population/delaware-cities?period=2021.
Harvard
U.S. Census Bureau (2026) Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals), Cities in Delaware by population, 2021 [Dataset]. Available at: https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/, via Invokely: https://invokely.ai/rankings/population/delaware-cities?period=2021 (Accessed: 12 October 2026).
BibTeX
@misc{census_cities_in_delaware_by_2021,
author = {{U.S. Census Bureau}},
title = {{Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals): Cities in Delaware by population, 2021}},
year = {2026},
howpublished = {Data set},
url = {https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/},
urldate = {2026-10-12},
note = {Accessed via Invokely, https://invokely.ai/rankings/population/delaware-cities?period=2021. Publisher attribution: U.S. Census Bureau. Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-12.},
}
RIS
TY - DATA
AU - U.S. Census Bureau
TI - Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals): Cities in Delaware by population, 2021
PY - 2026
DA - 2026/05/14
PB - U.S. Census Bureau
DB - Invokely
UR - https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/
L2 - https://invokely.ai/rankings/population/delaware-cities?period=2021
Y2 - 2026/10/12
N1 - Accessed via Invokely, https://invokely.ai/rankings/population/delaware-cities?period=2021.
N1 - Publisher attribution: U.S. Census Bureau. Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-12.
ER -
Use this data in your AI agent
Invokely serves this figure to AI assistants through MCP and to code through a REST API, with the source and citation attached. Ask your assistant:
Rank Cities in Delaware by population using official data, and cite the source.
rank_places {"indicator":"population","level":"municipality","within":"Delaware","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=population&level=municipality&within=Delaware&limit=10Questions
Which city has the highest population?
Wilmington, DE, with 70,833 in 2021, according to the U.S. Census Bureau.
Which city has the lowest population?
Milford, DE, with 12,331 in 2021.
Where does this ranking come from?
Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Annual estimates of the resident population for incorporated places, 1 July (Population Estimates Program, subcounty totals). Retrieved 2026-10-12.