Delaware Counties by Population (2025)
by Kristen Carney 
Updated: August 7, 2025
The most populous counties in Delaware are New Castle County with 588,093, Sussex County at 271,134, and Kent County with 192,690. You can get the most current Census population data for all 3 Delaware counties, sorted from the most populous counties in Delaware to the least, according to the 2024 Population Estimates Program.
Sure, you can copy this list right into your favorite spreadsheet tool. Or save yourself formatting headaches and grab the latest Delaware counties population data as a ready-to-use Excel™ file below. It's time to stop searching and start digging into data!
| Rank | County | Population |
|---|---|---|
| 1 | New Castle County | 588,093 |
| 2 | Sussex County | 271,134 |
| 3 | Kent County | 192,690 |
|
United States Census Bureau. Annual Estimates of the Resident Population: April 1, 2020 to July 1, 2024. Population Division. May 2025. |
||
Email Me When New Data Are Released
Join thousands of subscribers and receive just 2 (TWO!) emails a year in March and December when the US Census Bureau releases new population data for Delaware counties.
Products & Services
Plumbing
Connect
- 1-800-939-2130
- Contact Us
© Copyright 2025 Cubit Planning, Inc.