It is owned by the National Trust and has been sensitively restored to its probable 16th century appearance. Despite its name ("big house") it is very small by today's standards, but houses some old furniture and a collection of Welsh Bibles, including William Morgan's Bible of 1588. There are also other Bibles in many other languages, donated by visitors to the house from around the World.
"Wybrnant" is the name of the valley in which the house is located, and is often tagged onto the name to distinguish it from other "Tŷ Mawr"s. The origins of the word "wybrnant" are not wholly known. Whilst "nant" is a small stream, "wybr" is an old word for sky or cloud. Another school of thought is that the word is derived from a corruption of "(g)wiber", meaning adder/viper. According to myth , long ago a 'gwiber' was something quite different - a huge snake that could fly, and one lived in this valley.