24th February 2026

Fray’s River is a 5½ mile long river that branches off the River Colne just north of Denham Lock on the Grand Union Canal and rejoins it just south of Drayton Mill in West Drayton. The technical name for is an anabranch.

The section north of the confluence with the River Pinn is believed to have been man-made about 600 years ago to feed watermills in the Hillingdon parish. The southern section from the River Pinn junction to Drayton Mill was probably originally part of the River Pinn.

There are two islands formed by branches of the Fray’s River, one in north Cowley and one in West Drayton, possibly formed to regulate flow of water to mills.

Much of the bank of the Fray’s River is publicly accessible, although there are some sections where detours are required, particularly in West Drayton, Yiewsley and Cowley.

How the river got its name

The river is believed to be named after Sir John Fray who owned Cowley Hall (east of the mill of the same name) in the fifteenth century. He was an English lawyer and was elected Member of Parliament for Hertfordshire in 1419. He served on a number of commissions before being appointed Common Serjeant of London and Recorder of London in the 1420s. He later served as Chief Baron of the Exchequer. He had considerable experience of rivers and watermills. Fray had the commission for maintaining the navigation of the River Lea east of London in the 1430s. He owned watermills in Essex and interests in other property across the country. It is said that John Fray arranged for the cutting of a link from the River Colne to a tributary rising in Harefield to increase the water volume. He was knighted some time before 1459. He died in 1461 and was buried in the church of St Bartholomew the Less in the City of London.

Other names for the Fray’s River are the Uxbridge and Cowley Mill Stream, the Cowley Stream or the Colham Mill Stream.

The river is now channelled under the Grand Union Canal at Denham and Cowley Locks. This was required by the canal builders in order that the water supply to the mills was unaffected. Denham Deep Lock is the deepest lock on the Grand Union Canal. Just before it, the Fray’s River runs underneath. The long straight stretch to the north was built without a lock to avoid conflict with the Fray’s River and the mills along its course that existed 200 years ago.

Five Mills

In the 17th century the river allegedly powered five mills. Four of them are:

  1. Fountains Mill – Oxford Road, Uxbridge. This is a disused watermill for grinding corn. A mill existed on the site in 1530. It was rebuilt in 1796 after a fire and operated for about 150 years.  In 1914, the old water wheels were replaced by a steam engine and two water turbines. In 1954 the buildings were bought from the millers E and J Fountain by Glaxo Ltd. and later converted into a youth training centre. It has also been known as Town Mill, Mercer’s Mill and Frays Mill.
  1. Rabb’s Mill – Cowley Mill Road, Uxbridge. First mentioned by name in 1636. In 1769 it was in the occupation of Thomas Dagnall and was a timber building with tiled roof. By 1783 it had been rebuilt in brick. It was totally destroyed by fire in 1898, shortly after being refurbished with new machinery and a powerful gas engine, but was subsequently rebuilt. The new mill ran until March 1928 when it too was burnt down. The insurance company was not satisfied regarding certain aspects of the case and this time the mill was not rebuilt. The remaining walls were demolished in the late 1930s and a laundry built on the site. The existing Hale Hamilton valve factory built on the site in 1947 is constructed over the Fray’s River and incorporates part of the old mill building. The mill race was still to be seen in the early 1970s. Also known at various times as Robb’s Mill, Austin’s Mill and Dobell’s Mill.
  1. Cowley Hall Mill – Old Mill Lane, Cowley. This mill is shown on a map of 1641 and first mentioned by name in 1733. The mill was destroyed by fire in February 1864, but a new mill was built to replace it which is still standing. By 1878 it had been acquired by Grimsdale and Sons, corn merchants of Uxbridge. The west side is of wood as is the upper storey on all the other sides except for the north which is all brick apart from last few feet. Sadly, the upper storey has since been much altered as part of renovations to the structure; it now has conventional horizontally laid boarding over the framing on all sides, and is tarred or creosoted. On the side facing the road the boarding extends all the way down the ground, the brickwork having been demolished. The roof retains its scalloped eaves. Converted into private residential units around 2010. Also known at various times as Benbow’s Mill.
  1. Lower Colham Mill – Colham Mill Road, West Drayton. The mill was separated from the Manor of Colham in 1771 and sold to John Hubbard, a mealman, whose family had tenanted it since at least 1690. A watercolour of circa 1805 depicts the mill as a timber building on a brick lower storey with a tiled roof. By 1862 it was in the control of Edward and John Fountain, later of Fountains Mill in Uxbridge, the mill itself becoming known as “Fountains Mill” as did that at Uxbridge in its turn. In the early 20th Century it became the club house of West Drayton Golf Club. The mill was later acquired by the Rotary Photographic Works. It is probable that by the time it ceased work the largely timber building had been rebuilt in brick. No trace of the original wooden structure remains today.

West Drayton Mill on the River Colne was almost certainly existing when John Fray constructed his river.

The British writer George Orwell once taught at Frays College in Harefield Road, Uxbridge. It was on the banks of the Fray’s River and was named after it.

If you use “Walking in the Footsteps of an Edwardian” as your local walking companion, the Fray’s River features in walks 1, 4 and 5. The Fray’s River is also mentioned in Springall’s “Country Rambles Round Uxbridge”, but not in any detail.

Fray’s River OS map 1900

Fray’s River OS map 2026