Castle Mill Stream is a 5.5-kilometre (3.4 mi) longbackwater of theRiver Thames in the west ofOxford,England. It has its own secondary backwater, known as theWareham Stream, that is 0.5 kilometres (0.31 mi) long.[1]
The Castle Mill Stream leaves the main course of the River Thames at the south end ofPort Meadow, immediately upstream ofMedley Footbridge, split by the northern part ofFiddler's Island to the west. It flows between Port Meadow to the north andCripley Meadow (largelyallotments) to the south. It then passes under theCherwell Valley railway line and turns south, alongside the southern end of theOxford Canal and the railway tracks, across which is theCastle Mill graduate housing development of theUniversity of Oxford.
Further south, theIsis Lock gives access to the Oxford Canal, and the shortSheepwash Channel leads west under the railway tracks to the main stream of the Thames. The stream then flows past the vestigial remains ofRewley Abbey before reachingUpper Fisher Row, where the Wareham Stream leaves the main channel.[1][2]
The stream then flows under a series of bridges:Hythe Bridge (onHythe Bridge Street),Pacey's Bridge (onPark End Street},Quaking Bridge (betweenSt Thomas' Street andTidmarsh Lane), andSwan Bridge (onParadise Street and once known as Castle Bridge), outside the original medieval city walls of Oxford, nearOxford Castle. It is then re-joined by the Wareham Stream and continues underOxpens Road and rejoins the Thames immediately upstream of theGasworks Bridge.[1][3][4]
The Wareham Stream leaves the Castle Mill Stream at the upper end ofUpper Fisher Row. It then flows underLittle Hythe Bridge (onHythe Bridge Street),Pacey's Bridge (onPark End Street} andBookbinders' Bridge (onSt Thomas' Street) before re-entering the Castle Mill Stream near to the city centre campus of theCity of Oxford College.[1][3]
The stream was altered greatly inSaxon and earlyNorman times. There was a mill here even before the castle existed. In the winter of 1142, there was a siege at the castle.[5]Empress Matilda (aka Queen Maud, 1102–1167), the daughter and dispossessed heir ofHenry I, was there during her power struggle withKing Stephen (1096–1154). The queen escaped from the castle after her guards lowered her over the walls. She was clothed in a white dress that camouflaged her against the snow. Matilda crept through the enemy lines and across the Castle Mill Stream to escape to freedom.
In theMiddle Ages, the stream was used for navigation, at least above Hythe Bridge. During the 16th century, hay, wood, stone, and slate were unloaded at a wharf at Hythe Bridge.[6] When the Oxford Canal was built, it provided an easier route into the centre of Oxford, and in 1795-96Daniel Harris built Isis Lock to allow Thames river traffic to access the canal wharves. The stream then fell out of use for navigation.
Media related toCastle Mill Stream, Oxford at Wikimedia Commons| Next confluence upstream | River Thames | Next confluence downstream |
| Bulstake Stream (south) | Castle Mill Stream | River Cherwell (north) |
51°44′47″N1°15′49″W / 51.7464°N 1.2637°W /51.7464; -1.2637