The name probably means Rye Hill, Rey meaning rye and -don being an old English word for hill or rise). The village is close to the cliffs at Easton Bavents, and like the lost village of Easton, it was established before Southwold was. The parish church is St Margaret of Antioch.
There are three main roads through Reydon, around which the village is built. These are:
The village of Reydon lies to the north of the town of Southwold. The three roads from Wangford, Wrentham and Halesworth converge at Reydon corner about 100 metres from where Mights Bridge crosses over Buss Creek, which provides the only road bridge entry to Southwold.