All the Palladio drawings in England that do not belong to the RIBA were once owned by Inigo Jones, who acquired them in Italy in 1613. Most of Jones's collection was eventually bought by Lord Burlington in 1720, but a few stray drawings were sold in the 1670s and these are now at Worcester College, Oxford and Westminster Abbey, London. When Burlington's collection was given to the RIBA in 1894 by the 8th Duke of Devonshire, a few of them were overlooked and these are now at Chatsworth, Derbyshire, home of the present Duke of Devonshire.
Those drawings not at the RIBA can also be consulted by scholars. Write for an appointment to:
Chatsworth House, near Bakewell, Derbyshire DE45 1PP
Worcester College, Walton Street, Oxford OX1 2HB
Westminster Abbey, Library and Muniments Room, London SW1P 3PA