Total Population in New Castle County, DE
ACS 2024 5-Year Estimates
577,961
Rank #122/3,222 · #1 in DE
96th
New Castle 577,961
DE 1,021,191 -43.4%
US 330M
Total Population Trend
Rankings →Percentile Rank Over Time
Year-over-Year Population Change
National Distribution
How New Castle County's total population of 577,961 compares to all 3,222 U.S. counties. Values range from 33 to 9,808,667.
Distribution of Total Population Across All Counties
Ranking Context
Counties ranked closest to New Castle County for total population.
Nearby Rankings
Full ranking →| #119 | Jefferson County, CO | 579,377 |
| #120 | Union County, NJ | 579,290 |
| #121 | Delaware County, PA | 579,222 |
| #122 | New Castle County, DE | 577,961 |
| #123 | Baltimore city, MD | 573,243 |
| #124 | Dane County, WI | 572,674 |
| #125 | South Central Connecticut Planning Region, CT | 570,598 |
About Total Population
New Castle County, Delaware has a total population of 577,961, ranking #122 of 3,222 counties nationwide — 99.8% below the national value of 330M. Within Delaware, it ranks #1 of 3. This places it in the 96th percentile nationally.
Total population count from the American Community Survey. Source: U.S. Census Bureau, American Community Survey 2024 5-Year Estimates. All values are estimates derived from survey samples and are subject to margin of error. For more information, see our methodology.