Kent County, DE
Kent county covers the central portion of Delaware. It is the least populous county with an estimated 173,145 people, as of the 2018 census. Kent is home to Dover, the state capital and county seat. Dover was also the site of a NASA spacesuit manufacturing plant in the 1960s. The suits created in Dover were worn by astronauts Neil Armstrong and Buzz Aldrin on the Apollo 11 mission to the moon.
New Castle County, DE
With a population of 559,335, New Castle is home to around 60% of Delaware's residents. Though it’s the smallest county by geographic area, it’s population is more than the other two counties combined. Fort Christina, the first ever European settlement in what is now Delaware, was created in 1638 and is located in New Castle. Despite those early settlements, New Castle wasn't officially established until 1673.
Sussex County, DE
Though Seaford is the largest city in Sussex County, Georgetown is actually the county seat. There is some dispute as to who first settled in Sussex, but it’s believed that either Spanish or Portuguese explorers were the first Europeans to explore the area. Sussex County has a population of 215,551 and covers the entire bottom third of Delaware. This county has a variety of natural landmarks such as the Great Cypress Swamp and Prime Hook National Wildlife Refuge.