Rhyl, seaside town, Denbighshire (Sir Ddinbych) county, historic county of Flintshire (Sir Fflint), northern Wales. It lies on the coast of the Irish Sea at the mouth of the River Clwyd.
The town is predominantly a holiday resort, with extensive sandy beaches and excellent rail and road links with Lancashire and the English Midlands. Its promenade stretches for 3 miles (5 km), with a domed pavilion and the all-glass Royal Floral Hall. Prestatyn, which adjoins Rhyl to the east, is a similar holiday resort. Prestatyn has remains of prehistoric settlement, Offa’s Dyke (8th century), and a demolished castle (12th century). Pop. (2001) 25,390; (2011) 25,149.