A watercolour drawing showing the north front of Windsor Castle from the River Thames. The King's Engine House and the Wooden Bridge are to the right, Datchet Lane and Park wall to the left. In the foreground, a pair in a punt is on the river. Figures and a horse and carriage are on the path to the left. A wooden bridge over the river in the middle distance. Mounted with a black ink and grey wash border. Inscribed on the mount in pencil above, in an ornamental hand associated with the dealer Colnaghi, 'Windsor Castle by Sandby'. The same pencil hand appears on, for example, RCINs 914604, 914605, and 914713. EVII stamp, lower left corner.

Another version of the same subject, owned by Sir Joseph Banks, is in the British Museum (1958,0712.367), and although Oppé suggested that the present work is closer stylistically to William Marlow than Sandby, it may be a copy by Sandby of the Banks work, but of lesser quality. The King’s Engine House was designed by Sir John Vanbrugh in 1718 to pump water to the Castle. Datchet Lane and the pumphouse also appear in RCIN 917758.