Maydown (from Irish Magh Dúin meaning "plain of the stronghold")[1] is a small village and townland in County Londonderry, Northern Ireland.

Maydown is an industrial zone and was the site of the first DuPont production facility in Europe.

The DuPont site at Maydown is now the lead partner in the University of Ulster's Biodiversity Action on Industrial Site (BAIS) project that aims to enhance biodiversity on land close to industrial activity.

DuPont has developed 116 acres (0.47 km2) of its Maydown site into wildlife habitats open to the public and a visitor centre used by local schools.

It was also the site of Royal Air Force Station Maydown, USAAF airfield and later transferred to the Royal Navy as Royal Naval Air Station airfield, RNAS Maydown, during World War II.