The River Blyth in Suffolk, England, is a modest river about 19 miles (30.5 km) long. It rises near the village of Laxfield in the Suffolk countryside and flows southeastward through rural landscapes, including areas around Halesworth and Blythburgh.
Near Southwold, it forms a scenic tidal estuary that empties into the North Sea between Southwold (to the north) and Walberswick (to the south). The estuary mouth serves as Southwold's main harbour, which remains an active fishing port with a mix of saltmarshes, mudflats, and coastal scenery popular for wildlife, walking, and boating.
A short pedestrian Bailey Bridge and a traditional rowing-boat ferry allow crossings in the lower reaches. The area has a rich history of navigation (including the 18th-century canal) and has inspired many artists over the centuries.