Why old maps still matter on your walk

Harrow is often described as a London borough of suburbs, but look at an old map and a different place appears. Instead of rows of semi-detached houses and busy roundabouts, you see large open fields, narrow lanes, scattered farms and long, straight boundaries cutting across the clay. Those historic maps are not just curiosities. They are practical tools for understanding why modern Harrow looks the way it does.

Compare an enclosure map, a tithe map or the first Ordnance Survey sheets with a present-day street plan and you will notice something striking: many of today’s roads follow the lines of old field edges. A hedge that once separated two strips of land can still be traced in a garden boundary, a footpath or the curve of a suburban street. The past is not hidden; it is simply built over.

Reading the landscape: hedges, ditches and walls

Field boundaries on old maps appear as lines, but on the ground they were real features: hedgerows, ditches, banks, timber fences and occasionally stone or brick walls. Some of these have survived for centuries. In Harrow, ancient hedgerows are especially valuable because they preserve evidence of how the land was farmed before the railways arrived.

• Species-rich hedgerows often contain oak, ash, hazel, hawthorn, blackthorn and field maple. A hedge with many woody species is usually older than one dominated by a single shrub.
• Ditches and banks mark drainage on heavy clay soils, common around Pinner, Kenton and Harrow Weald. A shallow ditch beside a modern pavement may be the last trace of a field boundary.
• Boundary walls of brick or flint appear where estates and farms wanted something more durable, especially on the higher ground around Harrow on the Hill and Stanmore.
• Gates, stiles and gaps in long boundaries show where people and animals once crossed. These often became the alleyways and cut-throughs that still link streets today.

Footpaths that became streets — and paths that survived

Old maps show footpaths as dashed lines, often running along field edges or diagonally across open land. Many of these routes were later widened, tarmacked and renamed as roads. Others survived as public footpaths, squeezed between back gardens and allotments. In Harrow, the pattern is repeated from Pinner to Queensbury.

A path that once connected a farm to a church or a hamlet to a mill could become a residential street with a curious kink in it. That kink is a clue. Straight Victorian and twentieth-century roads tend to ignore older boundaries, but older lanes and paths bend around them. If you follow a road that suddenly jogs or narrows, you may be walking along a line that farmers knew long before anyone laid a pavement.

Harrow examples: from Pinner to Kenton

Pinner is a good place to start. The old village grew around a crossroads, with fields stretching north and west. Some of today’s lanes, such as those running towards Pinner Park and Nower Hill, follow boundaries that appear on nineteenth-century maps. The hedgerows beside them are not just decorative; they are fragments of a working agricultural landscape.

Further east, Kenton and Kingsbury were once part of a patchwork of fields and small holdings. Roads like Kenton Lane and Woodcock Hill have ancient origins, and the field patterns they crossed can still be sensed in the shape of later housing estates. In Harrow Weald, the open common and the earthwork of Grim’s Dyke remind us that boundaries were sometimes monumental, dug to mark territory or control livestock.

• Pinner: look for curving lane edges and hedgerows that run behind modern frontages.
• Harrow on the Hill: the steep streets and footpaths preserve routes that once linked the hilltop settlement to the fields below.
• Kenton and Queensbury: straight twentieth-century streets often cut across older field boundaries, but long garden walls can still follow them.
• Stanmore and Harrow Weald: woodland edges and common land show where boundaries were maintained by grazing rights rather than fences.

How to compare maps yourself

You do not need to be a professional historian to do this. Start with a modern street map or a mapping app, then find a historic map of the same area. Tithe maps from the 1840s, enclosure awards and Ordnance Survey sheets from the late nineteenth century are the most useful. The local studies collection at a Harrow library can help, and many old maps are available through county archive websites.

• Print or screenshot both maps at the same scale.
• Overlay them, or use tracing paper, and mark where boundaries match.
• Look for roads that follow field edges, especially long, slightly curved lines.
• Note where a footpath on the old map becomes a modern alley or pavement.
• Check field names on tithe apportionments — names like “Long Croft” or “Barn Field” often survive in street names.

What to look for on the ground

Once you have a likely boundary, go and walk it. Look for a hedge that is thicker or taller than its neighbours, a line of mature trees, or a wall that changes material halfway along. Check for old gates, stone markers or a ditch that still holds water in winter. Even a row of front gardens can preserve an old line if the houses were built at an angle to the street.

Field boundaries are quiet survivors. They do not announce themselves, but they reward close attention. Next time you walk through Harrow — along a suburban pavement, across a recreation ground or down a narrow footpath — imagine the map beneath your feet. The chances are you are following a line that a farmer, a surveyor or a parish boundary once drew, and that has quietly shaped the streets you know today.