New Castle County Demographics

A map of New Castle County's Population by Race

Race	2024 Pop	2020 Pop	2024 %	2020 %
White	302,505	303,265	52.3%	53.1%
Black	143,725	142,388	24.9%	24.9%
Hispanic	68,181	63,516	11.8%	11.1%
Asian	35,717	35,022	6.2%	6.1%
Multiracial	24,561	22,953	4.2%	4.0%
Native American/Other	3,272	3,575	0.6%	0.6%

New Castle County, Delaware has an estimated population of 577,961, a slight increase from the 570,719 recorded in the 2020 Census. The population is 52.3% White, 24.9% Black, 11.8% Hispanic, 6.2% Asian, 4.2% Multiracial, and 0.6% Native American/Other. This demographic dot map shows the population of New Castle County, with one dot drawn for each person counted by the Census, color-coded by race.

New Castle has become slightly more racially diverse since the 2020 Census. It is more diverse than Delaware overall. Demographers use a diversity index to measure the probability that two randomly selected individuals belong to different racial or ethnic groups. In New Castle County, that probability was 63.8% in 2020 and 64.5% in the most recent ACS estimates.

New Castle County is ranked the most populous county in Delaware, out of 3 counties. New Castle County was ranked the 1st most populous county in the 2020 Census.

New Castle County's White Population

302,505 residents of New Castle County, or 52.3% of the population, identify as White. The share of White residents in New Castle County is lower than in Delaware overall, where 58.1% of the population is White. New Castle County ranks 3rd statewide in terms of White residents as a share of the population, out of 3 counties.

Since the 2020 Census, New Castle County's White population has remained roughly the same. White residents' share of New Castle County's population has decreased from 53.1% to 52.3%.

New Castle County is less White than neighboring Salem County (70.2% White), Cecil County (80.4% White), Chester County (75.4% White), Delaware County (62.4% White), and Kent County (56.5% White).

New Castle County's Black Population

143,725 residents of New Castle County, or 24.9% of the population, identify as Black. The share of Black residents in New Castle County is slightly higher than in Delaware overall, where 21.4% of the population is Black. New Castle County ranks 2nd statewide in terms of Black residents as a share of the population, out of 3 counties.

Since the 2020 Census, New Castle County's Black population has remained roughly the same. Black residents' share of New Castle County's population has remained roughly unchanged at 24.9%.

New Castle County is more Black than neighboring Salem County (13.2% Black), Cecil County (7.1% Black), Chester County (4.9% Black), and Delaware County (21.9% Black). New Castle County is less Black than neighboring Kent County (26.4% Black).

New Castle County's Asian Population

35,717 residents of New Castle County, or 6.2% of the population, identify as Asian. The share of Asian residents in New Castle County is comparable to the share in Delaware overall, where 4.3% of the population is Asian. New Castle County ranks 1st statewide in terms of Asian residents as a share of the population, out of 3 counties.

Since the 2020 Census, New Castle County's Asian population has grown by an estimated 2.0%. Asian residents' share of New Castle County's population has remained roughly unchanged at 6.2%.

New Castle County is more Asian than neighboring Salem County (1% Asian), Cecil County (1.2% Asian), and Kent County (2.5% Asian). New Castle County is less Asian than neighboring Chester County (6.7% Asian), and Delaware County (6.3% Asian).

New Castle County's Hispanic Population

68,181 residents of New Castle County, or 11.8% of the population, identify as Hispanic. The share of Hispanic residents in New Castle County is comparable to the share in Delaware overall, where 11% of the population is Hispanic. New Castle County ranks 2nd statewide in terms of Hispanic residents as a share of the population, out of 3 counties.

Since the 2020 Census, New Castle County's Hispanic population has grown by an estimated 7.3%. Hispanic residents' share of New Castle County's population has increased from 11.1% to 11.8%.

New Castle County is more Hispanic than neighboring Salem County (11.3% Hispanic), Cecil County (5.6% Hispanic), Chester County (8.4% Hispanic), Delaware County (5% Hispanic), and Kent County (8.1% Hispanic).

New Castle County's Native American/Other Population

3,272 residents of New Castle County, or 0.6% of the population, identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other. The share of Native American/Other residents in New Castle County is comparable to the share in Delaware overall, where 0.6% of the population is Native American/Other. New Castle County ranks 3rd statewide in terms of Native American/Other residents as a share of the population, out of 3 counties.

Since the 2020 Census, New Castle County's Native American/Other population has declined by an estimated 8.5%. Native American/Other residents' share of New Castle County's population has remained roughly unchanged at 0.6%.

New Castle County is more Native American/Other than neighboring Salem County (0.5% Native American/Other), and Chester County (0.4% Native American/Other). New Castle County is less Native American/Other than neighboring Cecil County (0.7% Native American/Other), and Kent County (0.8% Native American/Other).

New Castle County's Multiracial Population

24,561 residents of New Castle County, or 4.2% of the population, identify as Multiracial. The share of Multiracial residents in New Castle County is comparable to the share in Delaware overall, where 4.5% of the population is Multiracial. New Castle County ranks 2nd statewide in terms of Multiracial residents as a share of the population, out of 3 counties.

Since the 2020 Census, New Castle County's Multiracial population has grown by an estimated 7.0%. Multiracial residents' share of New Castle County's population has remained roughly unchanged at 4.2%.

New Castle County is more Multiracial than neighboring Salem County (3.9% Multiracial), Chester County (4.1% Multiracial), and Delaware County (3.8% Multiracial). New Castle County is less Multiracial than neighboring Cecil County (5% Multiracial), and Kent County (5.6% Multiracial).

Sources: Most recent population estimates are from the 2020-2024 American Community Survey 5-Year Estimates. 2020 population counts and map data are from 2020 Census State Redistricting Data. Geographic data are from Census TIGER/Line Shapefiles.