Blythburgh is a small English village in an area known as the Sandlings, part of the Suffolk heritage coast. Located close to an area of flooded marshland and mud-flats, in 2007 its population was estimated to be 300. Blythburgh is best known for its church, Holy Trinity, internationally known as the Cathedral of the Marshes, which is a regular venue for the summer Aldeburgh Festival. The church has been flood-lit since the 1960s and is a landmark for travels on the arterial road to Norfolk.
Close to the village is the site of the Battle of Bulcamp (c. 653).