Opened in 1820 and enlarged in 1829, the Assembly Rooms were built under the instigation of W.E. Powell of Nanteos to the design of George Repton. Funds were raised by public subscription, and it was intended as a place for the wealthy and fashionable to meet. It has been subsequently used as a library and reading room, hall and Student Union building.

The building is symmetrical and is two storeys high and has a basement. It has twin hipped slate roofs with wide bracket eaves and rubble chimney stacks. The front is three-windows wide and the wall is finished in lightly-scribed stucco. A plain central arched porch with double panelled doors and fanlight above was added in 1829-30. The rear is five bays wide and two storeys high, with tall arched headed small-pane sash windows.

B.A.Malaws, RCAHMW, 06 April 2006.

The building housed the music department of Aberystwyth University (formerly the University of Wales, Aberystwyth), and also scenography (part of the Department of Theatre, Film and Television Studies).  The university named it 'Jospeh Parry Hall' (sometimes the 'Joseph Parry Building') after the first Professor of Music at Aberystwyth (1841 - 1903).

RCAHMW 2025