The Robin Hood Inn building has late medieval origins It is constructed in stone, with a wide, fifteenth-century four-centre doorway and is a rare medieval survival in Monmouth. It is has been desingated as a Grade II* listed building since 27 June 1952.
Monmouth was a centre for Catholicism. When Michael Watkins was landlord in the 1770s he allowed Mass to be celebrated in an upper room. The Penal Laws against Catholics were in force until the Papists Act of 1778, and Watkins was amongst those who successfully petitioned Monmouth magistrates to allow a building that would grow to be St Mary's Roman Catholic Church. This public house and the church that Michael Watkins lobbied for are two of the 24 buildings in the Monmouth Heritage Trail.