The state of Delaware is divided into three counties. New Castle County is the oldest (formed in 1664) while Kent County is the youngest (established in 1680).

New Castle County is the most populous, with a population of 538,479 people. Sussex County has the most land area (3,098 km2), while New Castle County has the smallest (1,279 km2).

Please find a list of all Delaware counties listed alphabetically below.

1. Kent County, DE
2. New Castle County, DE
3. Sussex County, DE