Welwyn Garden City is a town in the Welwyn Hatfield district, in Hertfordshire, England, 20 miles (32 km) north of London. It was the second garden city in England and one of the first new towns. It is unique in being both a garden city and a new town and exemplifies the physical, social and cultural planning ideals of the periods in which it was built. In 2021 it had a population of 51,505.