Known as Ham Chamberlayne from Ailufus le Hame the Chamberlain. And the name derives from Hamm (registered as such in the Domesday Book) which is Old English for  river meadow  plus a personal name and Preston is from Priest Farm which is also Old English preost and tun from land here that belongs to Wimborne Minster.

A chapel originally to Wimborne Minster became the Parish church in 1440 and is dedicated to All Saints and inside is an effigy of a priest that is dressed in a Black gown with a ruff around his neck, he is Miles Brownes who was rector here and died in 1630. There is a memorial to 'a certain soldier of Liftenant General Cromwell', the 'grant tyrant', who met his death in the River Stour at Hamm in 1644. Also here lies Henry Goldney who was excommunicated from the Church of Rome and was buried  in 1759.

There are two hamlets close by, Stapehill which had a Catholic Seminary in the 19th century and then a small convent of Cistercian Nuns founded 1847 with a chapel that was consecrated in 1851. The other hamlet is Longham which is about a mile to the South east and the manor was held by a Mr. Guest and he founded a charity for the poor there. There is a large bridge which crosses the Stour and was built c1740, a Wesleyan Chapel and a National School, a flour mill was also here and an independent chapel with a spire and clock that had a schoolhouse adjoining it.