a village and township of Wales, in the county of Flint, situated on the estuary of the Dee, 4 miles N.W. of Holywell. There is an elegant church here, which was built in 1845. The coal-pits in the neighbourhood are numerous, giving employment to the most of the inhabitants, and furnishing large quantities of coal for exportation. Mostyn stands on the railway between Chester and Holyhead; and communication is kept up by steamers with Liverpool. Pop. 2091.