Blagdon Hall (grid reference NZ21557705) is a privately owned English country house near Seaton Burn in Northumberland. It is a Grade I listed building. The house and estate have been in the ownership of the White Ridley family since 1698. The present Viscount Ridley is the science writer and banker Matt Ridley.
The hall was built in two phases between about 1720 and 1752 by Matthew White and his son Sir Matthew White, whose sister Elizabeth married Matthew Ridley (1719–1778), four times Mayor of Newcastle upon Tyne. It was substantially enlarged in the nineteenth century to designs by architects John Dobson and Ignatius Bonomi. Some of these additions were removed following a fire in 1944.
The stable block designed by James Wyatt in Palladian style in 1791 is Grade II* listed and a 19th-century folly in the grounds is Grade II listed. The gardens also contain the only surviving bronze of John Graham Lough's gigantic statue of Milo of Croton.