Southwold is a seaside town and civil parish on the North Sea, in the East Suffolk district, in the county of Suffolk, England. It lies at the mouth of the River Blyth in the Suffolk Coast and Heaths Area of Outstanding Natural Beauty, 11 miles south of Lowestoft, 29 miles north-east of Ipswich and 97 miles north-east of London, within the parliamentary constituency of Suffolk Coastal. At the 2021 Census, the population was 950.