The Boundary Brook leaving the Churchill Hospital area and running
down to the Lye Valley, where it is joined by the Lye Stream

The Boundary Brook runs from the north of the White Horse pub in Headington all the way down to the River Thames. Although it no longer marks a significant boundary, it still reveals its presence when roads suddenly change their names as it passes beneath or over them (see below). It is classified as a Critical Ordinary Watercourse (COW), which means that anti-flooding responsibility has been assumed by the Environment Agency.

Its original name as it ran through Headington was the Moor Ditch or Moor Brook, and once it reached the Cowley area it was known as the Cowley Marsh ditch and then the Withy Brook..

On 19 October 1867 Jackson's Oxford Journal reported on a meeting at Oxford Town Hall with the two Assistant Boundary Commissioners for the Oxford district “with the view to ascertain whether the Boundaries should be enlarged so as to include within the limits of the City all premises which ought, due regard being had to situation and other local circumstances, to be included therein for the purpose of conferring upon the occupiers thereof the Parliamentary Franchise for such City”. Mr Eagleston said:

The Local Government Act presented a water-course over all the distance, started at the river, went nearly straight to Cowley Road, crossed the Marsh to the old bridle road leading to Bullingdon Marsh ditch [Barracks Lane], thence it continued straight into the Headington Road, thus presenting a clear line of limitation without any of the difficulty of the Local Board Boundary.

In 1868 this brook became the parliamentary boundary of Oxford, and henceforth was interchangeably known by its old names and its new one, the Boundary Brook.

For 21 years from 1868, however, the City boundary remained in Headington at Pullen's Lane. It was in 1889 that this brook became an even more significant boundary, when Oxford was extended eastwards as far as this brook and parts of Headington and the Cowley and Iffley Road area were taken into the city.

• Map of 1868 showing the new city boundary of 1889 marked in red.

For the next forty years this brook marked the line where Oxford met three neighbouring villages (Headington, Cowley, and Iffley). In 1929 those villages were themselves taken into the city, so the Boundary Brook lost its significance (but retained its name).

Some stones marking the new 1887 boundary were set up ready for the next Mayor's perambulation, which took place in 1892. The two following two in Headington are situated at points where the brook is piped underground:

Left: At Cuckoo Lane near Woodlands Road. The 1889 city boundary, which hitherto ran eastwards, makes a sharp right-angled turn to the south here near the start of the brook, and this stone marks the corner point is marked

Right: Opposite Headley Way at the point where the Headington and London Roads meet

There was a special beating of the bounds in 1892 by the Mayor, Frederick Ansell. (Just after the party crossed the London Road in Headington, when they were walking in single file along the back of the present Valentia Road, they got mixed up with a wasps’ nest: only one man was reported stung, though most of the others were “discomfited”.)

Where does the Boundary Brook originate?

The Boundary Brook starts to the north of the White Horse pub, probably near this boundary stone on Woodlands Road, but is underground at this point.

The enumerator of the 1891 census describes it simply as a watercourse when outlining his route:

• New Headington census: “the watercourse from the said White Horse Beerhouse to the footpath leading from Old Headington to Oxford [Cuckoo Lane]”;
• Old Headington census: "along the footpath leading from Oxford to Headington [Cuckoo Lane], around Mr Davenport’s Plantation [now the site of Headington School] to the Watercourse, following the said Watercourse southerly to the London Road near the White Horse Beerhouse.

Jeffries’ 1769 map of Headington (above), drawn before the London Road was created, shows the brook starting south of Cuckoo Lane (then the main route by foot to Old Headington) and running straight across Old Road.

Route of the brook from Headington to Cowley

Above: the Boundary Brook in 1939, when it still ran above ground
to the west of the present White Horse (marked “P.H.”).
Headley Way did not then exist. “C.D.” means “County & District Boundary”;
“B.S.” refers to the boundary stone shown above

The Boundary Brook today runs underground in a southerly direction past the west side of the White Horse, cutting under part of Headley Way. This section of Headley Way between Woodlands Road and the Headington/London Road was not built until the 1950s, and prior to that the brook ran in the open here, with Headington School on one side and the pub the other, and steam engines would refill their water from it. The cottage that stands in the eastern corner of the Headington School grounds was appropriately called Boundary Cottage. See Oxford Journal Illustrated, 11 March 1925, for a photograph of what is described as a brick-lined ancient culvert near the White Horse about to be destroyed in a new road-making scheme.

The brook crossed the main road underground at the point where Headington Road, Oxford meets the London Road, Headington. The fact that from 1889 the Headington Road was in the city of Oxford but the London Road was in Headington explains why today what appears to be the same road suddenly changes its name at this point.

The brook used to re-emerge into daylight at the bridge on the south side by Nos. 236/238 Headington Road. It was several feet below street level at this point, and a fence was erected along part of Brookside as a safety measure. It now continues underground.

It divides the back gardens of the houses on the east side of Valentia Road (part of the Gipsy Lane council estate) from those on the west side of the appropriately named Brookside, which was named after Brookside House, now Headington Junior School, which stands on its eastern bank. Until 1975 the brook still ran in the open here, but then the City Council culverted it all the way from the London Road to the Old Road. In the nineteenth century, this part of the brook marked the whole eastern boundary of Highfield Farm.

The brook crosses underneath Old Road at its lowest point about half-way between Valentia Road and Highfield Avenue, just to the west of Finch Close. Once again there used to be a name change here emphasizing the crossing of a border, with the road to the west of the brook called Shotover Road, Oxford and the road to the east Old Road, Headington; but this demarcation has not survived, as in the late 1940s the whole road was renamed Old Road and renumbered.

Then after a very short bend to the east the brook emerges at last into daylight and runs due south between the University of Oxford’s Old Road Campus to the east and Mileway Gardens to the west, passing under a bridge at Roosevelt Drive. This next part, with the Warneford Meadow to the west and the Churchill Hospital to the east, is designated the Boundary Brook Wildlife Corridor.

It continues south along the west side of the Churchill Hospital, and this large balancing pond/lake near the Oxford Cancer Centre is designed to collect surplus storm water running off the built-up Churchill site:

The brook then turns south-east and runs along the edge of the golf course and then down to meet the Lye Stream in the Lye Valley Nature Reserve.

The rocks south of the Churchill Hospital are Beckley Sands, which have a high iron content, so the springs feeding the Boundary Brook are rich in iron. This forms harmless iron oxide (rust) when exposed to the air, and this can often be seen on the surface of the springs and the Boundary Brook itself at this point (right).

The brook then runs south-east through the golf course and then south west, emerging in Barracks Lane at bottom of the hill. It is not possible to follow it at this point, but it is possible to take the footpath from Lye Valley over the golf course to Barracks Lane and turn left and proceed as shown below.