According to the US Census Bureau population estimates, there were 965,479 people living in Delaware in 2018. New Castle was the most populated county with 557,550 residents, followed by Sussex with 229,389 residents, and Kent with 178,540 residents. Kent with a population of 178,540 was the least populated county in Delaware in 2018.

Use the map below to interactively explore the population of each county in Delaware in 2018. The data can also be explored further by sorting and filtering with the table below.