Duke of Grafton is a title in the Peerage of England. It was created in 1675 by Charles II of England for Henry FitzRoy, his second illegitimate son by the Duchess of Cleveland. The most notable duke of Grafton was Augustus FitzRoy, 3rd Duke of Grafton, who served as Prime Minister from 1768–1770. The Dukes "created" and owned the London district of Fitzrovia, so named for their family name. The title of the dukedom refers to the Honour of Grafton in the southeast of Northamptonshire, the titular village now being called Grafton Regis.