How to Read Follies on UK Maps: Symbols, Contours and Rights of Way

Most follies are found by accident. A black speck on the map, a mile from the nearest lane, turns out to be a roofless tower with a Gothic window and no staircase. The map told you the building was there; it just didn't tell you what to expect. Learning to read symbols, contours and access markings properly is what turns a lucky find into a repeatable one, and Ordnance Survey sheets are far more forthcoming about follies than most walkers realise.

The legend on the sheet in your hand

Every OS map carries its own key, and that key shifts between scales and editions. Two habits will save you more time than any gadget. First, read the legend printed on the sheet you are actually holding, not the one you remember from a previous trip. Second, use an Explorer (1:25,000) rather than a Landranger (1:50,000) when you are hunting structures. At 1:25,000 a small tower gets its own symbol; at 1:50,000 it often vanishes altogether.

Symbols worth hunting for

• Names set in blackletter or Gothic type. This script is reserved for antiquities, so "Castle" or "Fort" printed that way usually means earthworks or a scheduled monument rather than a habitable building.
• Labels such as Tower, Tower (disused), Monument, Mausoleum, Prospect Tower, Belvedere or, occasionally, Folly itself.
• A name with no building symbol beside it. Often the structure has gone but the survey name survives, which is a useful prompt to check older maps.
• A spot height printed beside a lone building, which suggests the surveyor thought the position worth recording.

Reading a building's shape and size

Filled black usually means a substantial roofed building; a thin outline can mean something smaller, open or ruinous, though you should never treat that as a guarantee. What you cannot do is judge scale from the symbol. Small buildings are exaggerated so they remain visible, so a tower drawn boldly may be no larger than a garden shed, while a big house is drawn true to size. A symbol a couple of millimetres across at 1:25,000 represents something under about fifty metres wide. Treat the symbol as a location, not a measurement.

Contours: why the folly stands there

Follies were built to be seen and to be seen from, which makes contours unusually informative. Contour intervals commonly run at five metres on gentler ground and ten metres in the hills, so always check the interval before you start counting.

Look for the places where the land changes character. Contours that bunch tightly, then relax, then bunch again usually mark an escarpment edge, and that edge is exactly where a prospect tower belongs. A ring of closed contours around a single small summit is a knoll, and a folly on a knoll is nearly always deliberate. If a triangulation pillar sits nearby, the summit was chosen twice over: once by the Ordnance Survey for its sightlines, and once by whoever paid for the tower.

Then trace the view. If the folly shares a contour band with a country house a mile away, or sits directly above a designed parkland, you have probably found the reason it was built.

Access land is not a right of way

Open access land appears on Explorer maps as a pale tint, usually with a walking figure symbol. In England and Wales this mapping reflects the Countryside and Rights of Way Act 2000; in Scotland access is broader and governed by the responsible access principles of the Land Reform (Scotland) Act 2003. Either way, access land is a patch of ground where you may roam, not a route.

Two catches matter for folly hunting. Certain categories of land are excepted from access rights, and buildings and their immediate surroundings are generally among them, so the right to cross a hillside does not automatically give you the right to enter, climb or potter about inside the tower itself. Access land can also be closed on certain days for land management, so check the relevant access authority's website before a long journey. If in doubt about a specific structure, ask the landowner. This is general guidance, not legal advice.

Green lines: public rights of way

Public rights of way are shown in green on Explorer maps, and the exact pattern of dashes, dots and small plus signs tells you which kind you are looking at. A simple dashed line is usually a footpath; add the plus signs and you are generally on a bridleway, open to walkers, cyclists and horse riders. Dotted lines tend to indicate byways with greater vehicle rights.

On the ground, painted waymark discs follow the same logic: yellow for footpaths, blue for bridleways, red for byways open to all traffic, purple for restricted byways. Remember that a right of way is a line, not a corridor. Where a path crosses cultivated land it should be reinstated and kept clear, but the legal line stays where it is drawn, so carry the map rather than trusting a worn track through the crop. Waymarks go missing, gates get wired shut and paths are occasionally diverted; the definitive map held by the local highway authority is the record that counts.

Grid references and cross-checking

Take a six-figure grid reference for anything you plan to visit. Digits along the corridor first, then up the stairs. Six figures pin the spot to a hundred-metre square, which is close enough to find a tower in a wood.

Then cross-check before you travel. The National Library of Scotland's online map collection holds historic OS sheets, and a folly that appears clearly on a 1900s edition may be a stump today. For background, search the heritage records: the National Heritage List for England, Coflein in Wales, Canmore in Scotland, or the local Historic Environment Record. Many entries will tell you outright whether a structure was built as a folly, and roughly when.

A practical routine before you go

1. Confirm the scale and read the legend, including the contour interval.
2. Note a six-figure grid reference and check the site on historic maps and aerial imagery.
3. Identify the nearest legal access: a green right of way, a patch of open access land, or a permissive path.
4. Check for temporary closures or diversions on the access authority's website.
5. Take the paper map as well as the phone, and a compass if the route leaves waymarked ground.

Finally, treat the structure itself with caution. Follies are often unroofed, unmortared or hollow underneath, and a tower that looks sound from the path can shed masonry without warning. Look, photograph and enjoy from ground level; leave the climbing to those with the owner's permission and the right equipment.

Photo: MasterTux / Pixabay