Cosgrove aqueduct is a navigable cast iron trough navigable aqueduct that carries the Grand Union Canal over the River Great Ouse, on the borders between Buckinghamshire and Northamptonshire at the northwest margin of Milton Keynes in England.

Initially flights of locks, four at the southeast and five at the northwest, were used to allow the canal to descend to cross the river on the level, and this arrangement came into action in 1800.

Although Jessop is sometimes blamed for the failure of the first structure, the collapse actually led to a legal dispute with the original contractor.

The issue went to trial, with damages eventually being awarded to the Grand Junction Company for loss of trade while the canal was out of action, and the cost of the replacement aqueduct.

As a temporary measure the lock system originally installed was brought back into use, and Benjamin Bevan, an engineer employed by the canal company, designed a replacement structure.