The Buckingham branch of the Grand Junction Canal ran from Old Stratford to Buckingham. The branch was authorised by an Act of Parliament passed in March 1794.
Like the Old Stratford branch the original plan was to canalise the River Ouse from Wolverton to Buckingham via Old Stratford. This route would climb the Ouse valley using a series of locks. This all changed when the crossing of the River Ouse at Wolverton was made at high level via an aqueduct. The new route ran from Old Stratford up the side of the Ouse Valley and started some 40ft above the river. This route change meant that only two locks were needed to reach Buckingham.

In May 1800 the Marquis of Buckingham agreed to lend the money needed to build the branch, to the Grand Junction Canal Company. Once the work had finished on the main line, work started on the Old Stratford branch, then the Buckingham branch. The Grand Opening was at Buckingham on the 1 May 1801, when the Marquis of Buckingham and other committee members arrived in a narrow boat. This narrow boat led a procession of 12 narrow boats carrying coal, slate and other goods. The procession was greeted at Buckingham basin by a large crowd and the firing of a cannon.

The canal very quickly became very important to the agricultural area around Buckingham. carrying 20,000 tons of cargo each year. This was made up of hay and straw exported to London for their thriving horse-drawn traffic, with imports in the area of coal, stone and other goods, remaining high for the next 50 years. Once the Bletchley to Banbury railway (with a station in Buckingham) was completed in 1850, trade started to diminish with the last traffic being to Deanshanger in 1935.

The branch remained open until it was temporarily dammed at bridge 1 during the Second World War. The reason for this was that the branch had been poorly maintained for years. This lack of maintenance caused the branch to draw water from the main line of the canal, so to protect vital wartime traffic on the main line the dam was installed.

This dam was still in place when in 1960 a report commissioned by the then nationalised British Transport Commission recommended its closure. The Old Stratford Branch was officially abandoned in 1964, with the exception of the length from Cosgrove to bridge 1 which is still open today and used as a marina.