Raglan Castle () is a late medieval castle located just north of the village of Raglan in the county of Monmouthshire in south east Wales. The modern castle dates from between the 15th and early 17th centuries, when the successive ruling families of the Herberts and the Somersets created a luxurious, fortified castle, complete with a large hexagonal keep, known as the Great Tower or the Yellow Tower of Gwent. Surrounded by parkland, water gardens and terraces, the castle was considered by contemporaries to be the equal of any other in England or Wales.