Trwyn Du Lighthouse, also known as Penmon Lighthouse, is a lighthouse between Black Point near Penmon and Ynys Seiriol, or Puffin Island, at the eastern extremity of Anglesey, marking the passage between the two islands.

In the United Kingdom, the term listed building refers to a building or other structure officially designated as being of special architectural, historical, or cultural significance; Grade II* structures are those considered to be "particularly important buildings of more than special interest". Listing was begun by a provision in the Town and Country Planning Act 1947. Once listed, strict limitations are imposed on the modifications allowed to a building's structure or fittings. In Wales, the authority for listing under the Planning Act 1990 rests with Cadw.