Delaware Population By County in 2021

Based on the US Census Vintage data estimates, in 2021, the population of Delaware was 1,004,881. Among all Delaware counties, New Castle had the highest population (572,029), followed by Sussex (247,809), and Kent (185,043). Kent was the least populated county (185,043).

Hover over or click on the counties in the map below to see the populations. The data can also be found in a table below. You can use the table to sort, filter, and explore the data further.

You can see similar information for other states and by state for the United States.