Welwyn is a village in Hertfordshire, England.

Situated in the valley of the River Mimram, it was first settled in the Iron Age. The Belgae colonised the area in the 1st century BC, and later it was settled by the Romans. Many Roman artefacts have been found, and the remains of a Roman bath house may be visited. Much later, in the 17th century, as it lies on the old Great North Road, it became an important staging post and a number of Coaching inns remain as public houses.

A Norman church was built on the site about 1190. The nave of the present church (St Mary's), was built in the 13th century, the chancel arch being the most obvious early structure. There are two medieval corbels at the east end of the south aisle. Patronage of the church passed through several hands until in 1549 it was sold to the Wilshere family, who lived at The Frythe until relatively recently.

See also: Welwyn Garden City