The Manx name for Tynwald Hill: the hill of the church of John. The name preserves the pre-Norse Christian chapel dedicated to St John that stood at the site before the Vikings established their thing-vollr there. Three layers of meaning in one place name: the Celtic sacred site, the Christian keeill, and the Norse assembly. The etymology demonstrates the accommodation already operating inside the constitutional structure.

Cronk-y-Voddy Straight, from about 10.75 miles, is a very fast but bumpy and undulating stretch of the A3 road. Nearby sections of this road, including around Handley's Corner and the 11th Milestone, saw repair work carried out between 2003 and 2006.

The site of an early medieval chapel or keeill, thought to have been in use between circa AD500 and AD1000.  The site is at the north side of the highroad to Cronk-y-Coddy. The name of the keeill is lost but the field is still known as 'Chapel Field'. Several people remembered the removal of the foundations and ploughing of the site in about 1880. Mr Corlett stated that stones from it were placed along the east side of the lane leading into the field where they can still be seen. Nothing remains to mark the site but the 1869 1:2500 scale Ordnance Survey map shows the mound on which the keeill stood.  It would have measured circa 12 metres by 7 metres. Evidently it had already been greatly reduced by the plough by that time.

Industrial settlement in Braddan, on the outskirts of Douglas, developed around a nineteenth-century textile works. A note added to the Manx Society edition of Feltham’s Tour through the Isle of Man described the works at Cronkbourne as having changed considerably from their earlier use. Linen manufacture had ceased, and the factory was instead producing sailcloth and fishing nets using both water and steam power. The proprietor, William Fine Moore, employed about 200 people. For the workforce he built what the editor called “quite a village” of superior cottages. A schoolroom and accommodation for its mistress were also provided. The schoolroom was licensed for public worship, with a service held there every Sunday evening at half past six and on other occasions. The same account remarked that the countryside around Tromode and Cronkbourne had been greatly altered since Feltham’s visit and described the valley looking towards the mountains as particularly beautiful. William Fine Moore also appears in the membership lists of the Manx Society as a member of the House of Keys, resident at Cronkbourne in Braddan.

Industrial settlement in Braddan, on the outskirts of Douglas, developed around a nineteenth-century textile works. A note added to the Manx Society edition of Feltham’s Tour through the Isle of Man described the works at Cronkbourne as having changed considerably from their earlier use. Linen manufacture had ceased, and the factory was instead producing sailcloth and fishing nets using both water and steam power. The proprietor, William Fine Moore, employed about 200 people. For the workforce he built what the editor called “quite a village” of superior cottages. A schoolroom and accommodation for its mistress were also provided. The schoolroom was licensed for public worship, with a service held there every Sunday evening at half past six and on other occasions. The same account remarked that the countryside around Tromode and Cronkbourne had been greatly altered since Feltham’s visit and described the valley looking towards the mountains as particularly beautiful. William Fine Moore also appears in the membership lists of the Manx Society as a member of the House of Keys, resident at Cronkbourne in Braddan.

A post-medieval house in Crockbourne Avenue, Douglas.

The site of a 19th century residence associated with Cronkbourne industrial village.

Cronkbourne House takes its name from the Manx word "cronk" (hill) combined with the English "bourne" (stream), and was established by James Moore. His son, William Fine Moore, went on to develop the neighbouring Cronkbourne Village in the 1840s as housing for workers at his nearby flax mill, and lived at Cronkbourne House overlooking the community he was building. The scheme is thought to have been the only model industrial village of its kind on the Isle of Man outside the mining industry, and predates better-known English examples such as Port Sunlight, Bournville and Saltaire.

The site of a post-medieval water mill which had been converted for use as a laundry. This is likely associated with the Moore family's Tromode sailcloth and flax works nearby: after the works closed in 1905, the site and associated buildings passed to other businesses, including a laundry run by Clucas'. William Fine Moore also developed the adjoining Cronkbourne Village in the 1840s to house mill workers, named from the Manx 'Cronk' (hill) and English 'bourne' (river); the artist Archibald Knox was born there in 1864.

The findspot of an early prehistoric flint scatter.

Cronkbourne Village, near Tromode just outside Douglas, was developed in the 1840s by William Fine Moore to house workers at his nearby flax mill, with Moore himself living at Cronkbourne House overlooking the settlement. Its name blends the Manx 'cronk' (hill) with the English 'bourne' (stream), reflecting its position by the River Glass. The terrace of workers' cottages included several different house types, and the celebrated Arts and Crafts designer Archibald Knox was born in the village in 1864, his father having moved to the Island from Scotland to work at Tromode. The village survives today as a rare and largely intact example of planned Victorian industrial housing on the Island.

Cronkbourne Village is almost the only example in the Isle of Man of housing erected by a firm for its employees. It was built, probably between 1846 and 1850, by the Moore family for the workers in their sail-cloth mill which was situated a little higher up the river.  The dwellings have been bought and modernised by Braddan Parish Commissioners. The forty-two houses were arranged in two parallel terraces at right angles to the river and despite varied dimensions and arrangement there were only two basic ground-floor plans consisting of two (living room and rear scullery) or three rooms. Except for numbers 8-17 the houses are two-storeyed. Some two dozen cottages are arranged in two rows parallelling each other separated by a green area on whose axis is focussed a community hall. All of the cottages are of masonry construction cement rendered with slate roofs. Although there is some variation in the designs with a series of bungalows rising with the contour of the ground and some dormer treatment of cottages on the flat land, all buildings are in continuous terraces with a common front plane for their respective rows. The complex thus creates a self contained community around the green space even though one of the rows of cottages backs onto the green while the other fronts onto it. The majority of the cottages have consistent decoration to their rather simply articulated fenestration.  The 'hall' is built of stone with a matching pitched slate roof rising to a bell housing in the gable over the original entrance from the village green. The hall however has been somewhat altered and is now used for non-community purposes. No interior inspections have been made.

A large granite boulder in a private garden at Cronkbreck has been interpreted to be the possible base of a 13th or 14th century cross from "The Crosh", or possibly a medieval font. The "boulder" measures 18 inch long x 11-12 inch wide x 10-13 inch high with rectangular hollows cut into it.

A record for the post-medieval farmhouse at Cronkbreck farm.

A private dwelling.

The findspot of a Neolithic stone axhead, found during well-sinking.  The site is now occupied by a modern dwelling and garden.

The findspot of an early prehistoric flint scatter in a field which now extends from the farm house to Lough Mallow.

The findspot of a Neolithic trimmed flint flake and another flint implement.  The grid reference is located to the centre of former OS Field No 2693 for indicative purposes only.

The site of a cliff-top Iron Age promontory fort. The natural defences consist of a precipitous drop in the West and steep slopes to re-entrants on the north and south. To complete the defence in the unprotected east side an outer ditch, average 5.0 metres wide and 0.8 metres deep from the outer lip, has been constructed from re-entrant to re-entrant. Unlike the typical promontory forts on the Isle of Man, the interior of the fort, which is grass and gorse covered and shows no trace of internal construction, is at approximate the same level as the surrounding ground. To compensate for this a stronger than usual inner bank has been provided, 1.0 metres upper width, 3.0 metres outer height and 2.8 metres inner height. There is no trace of an entrance and part of the inner bank is eroding away.

A ruined structure at Cronkmooar.

Crosby Crossroads, at about 4.8 miles, marks the course's passage through the village of Crosby, home to roughly 900 people. It is a straightforward place-name point rather than the site of any documented racing incident.

An emergency excavation was carried out here in 1958-9 of a disturbed burial site revealed by ploughing at Crosby Farm, Bride.  The site consisted of a megalithic capstone above a shallow pit filled with charcoal. The excavation yielding no datable finds.

Crosby Jump sits at the 5-mile marker from the Grandstand, right where the course leaves the village of Crosby at one of the highest points on its westward run. The spot hosted an official TT Fanzone in 2012, making it one of the rare named points on this stretch with a specific event tied to it.

This was the site of a now lost stone which may have been a large erratic boulder of felspathic sandstone or grit, but possibly a prehistoric standing stone which had been set up on end to mark the site of a burial place. It was inclined to the southeast and measured 1.7 metres high by 1.9 metres wide by 1.0 metre thick at the base and was approximate 1.0 metres square at the top. A number of small probable field clearing stones were placed around it. No trace of a mound was found. It was not a rubbing post.

Prehistoric spindle whorl. A stone spindle whorl, of Bronze or Iron Age date, was found in the Crosby vicarage garden by the donor, and given to the Manx Museum in 1931. The spindle whorl is of a reddish stone,and measures 33mm in diameter. The object is in the Manx National Heritage collections, accession no. 1954-2928.