Plas Mawr (English: Great Hall) is an Elizabethan townhouse in Conwy, North Wales, dating from the 16th century. The property was built by Robert Wynn, a member of the local gentry, following his marriage to his first wife, Dorothy Griffith. Plas Mawr occupied a plot of land off Conwy's High Street and was constructed in three phases between 1576 and 1585 at a total cost of around £800. Wynn was known for his hospitality, and the household was supported by Wynn's local dairy herds, orchards and gardens.