It was named for Thomas Hay, Viscount Dupplin (later 9th Earl of Kinnoull),[5] as he was known when he served on the Board of Trade and Plantations in England in the 1740s.

In the 19th century, he migrated to Leon County in the panhandle of Florida, with other North Carolinians during the period of Indian Removal in the 1830s–1840s.

[7] Duplin County is located in the humid subtropical climate (Köppen climate classification Cfa) zone, with mostly moderate temperatures year round.

Winters are mild across Duplin, with the warmest winter temperatures found in the southeastern areas of the county due to the influence of the nearby Atlantic Ocean.

24.50% of all households were made up of individuals, and 11.10% had someone living alone who was 65 years of age or older.

Duplin County is a member of the regional Eastern Carolina Council of Governments.

Duplin County is important in raising animals for food.

Duplin County is home to James Sprunt Community College.