La Dolphine, Hillsborough
La Dolphine was not a music venue but a large mansion and estate in Hillsborough.
The Grateful Dead played at a debutante dance at the house in September 1966. The Dead played on a stage setup in the gardens of the house whilst inside Al Trobbe (the "pianist with a thousand fingers") and his orchestra played a set in the ballroom.
Big Brother & The Holding Company played at a debutante dance at the house in September 1967.
The estate, at 1761 Manor Road, was built in 1913 and originally called Newmar.
Additions and corrections are welcome