The River Lavant is a winterbourne that rises at East Dean and flows west to Singleton, then south past West Dean and Lavant to Chichester. From east of Chichester its natural course was south to the sea at Pagham, but the Romans diverted it to flow around the southern walls of Chichester and then west into Chichester Harbour.

East Dean is a village and civil parish in the District of Chichester in West Sussex, England. The village is in a valley in the South Downs, 5+1⁄2 miles (9 km) north-northeast of Chichester on a narrow road between Singleton on the A286 and Upwaltham on the A285 road. The village pond is considered to be the source of the River Lavant.