Gregynog (Welsh pronunciation: [ɡrɛˈɡənɔɡ]) is a large country mansion in the village of Tregynon, 4 miles (6.4 km) northwest of Newtown in the old county of Montgomeryshire, now Powys in mid Wales.

The Sudeleys were also pioneers of the use of concrete in the building of new cottages and farmhouses on the Gregynog estate, and many Cadw-listed examples can still be seen in Tregynon and the surrounding countryside.

[2] Gregynog was bought by Margaret and her elder sister Gwendoline Davies in 1920 with the intention of establishing a centre of excellence for the arts, crafts and music which would enrich the lives of the people of Wales in the aftermath of the World War One.

Many famous names are associated with the Gregynog Festivals, including Gustav Holst, Ralph Vaughan Williams, Edward Elgar and Sir Adrian Boult.

Since Margaret Davies's gift of Gregynog to the University of Wales in 1960, the hall has hosted conferences, seminars and summer schools from every academic discipline.

[11] The Hall continues to operate as an historic house conference centre and now wedding venue, offering tourist accommodation for visitors to the gardens and grounds.