This is the town of Purley.
It's on three OS Landranger maps.
You know Landrangers, they're the pink ones. There are 204 Landranger maps, each drawn to a scale of 1:50000, and between them they cover the whole of Great Britain and its islands.
Most people live on one OS Landranger map. The maps tend to align precisely with their neighbours so places appear on one or the other. But sometimes the maps overlap, generally slightly, nudged for reasons of geography and topology. Several people therefore live on two OS Landranger maps, usually near the edge of both.
I live on one OS Landranger Map [177, East London], but if I lived in Whitechapel I'd be on two OS Landranger maps because [176, West London] covers that as well. London's a bit of a special case for OS Landrangers because 176 and 177 overlap to cover the capital and also overlap with all the pink maps around the edge.
Purley gets lucky because it falls in the bottom right corner of [176, West London], the bottom left corner of [177, East London] and along the top of [187, Dorking & Reigate]. You might not think being on the edge of three maps is lucky, but it's a lot more useful than being on the edge of just one.
Other places around London on three OS Landranger maps include Enfield [166, 176, 177], Billericay in Essex [176, 177, 178], Chobham in Surrey [175, 176, 186] and Snodland in Kent [177, 178, 188]. Around the country the environs of Perth [52, 53, 58], Berwick [67, 74, 75], Scarborough [94, 100, 101], Wisbech [131, 142, 143] and Nailsea [171, 172, 182] are also on three maps, but they're very much the exception.
I think only one place in Great Britain appears on four OS Landranger maps and it's just north of Leominster in Herefordshire. Here maps [137, Church Stretton & Ludlow], [138, Kidderminster & Wyre Forest], [148, Presteigne & Hay on Wye] and [149, Hereford and Leominster] coincide, creating an overlap 3 miles wide and 5 miles deep. Villages in this rare fourway space include Eyton, Luston and Larpole, also residents of Ridgemoor Road on the very northern edge of Leominster.
If you want to check this for yourself, the place to look is the summary map on the back cover of any OS Landranger map. You can find a useful jpg copy of that map here. Alternatively the Ordnance Survey has an amazing Map Selector online, its function to identify all their maps that cover a particular place. Enter the name of a place or click a particular point and a very precise set of map boundaries appears. You may have to turn off the Explorer maps to see the Landrangers more clearly.
Which brings me to the Explorers, the orange ones. There are 403 Explorer maps, each drawn to a scale of 1:25000. Some are larger than others, particularly the OL (Outdoor Leisure) maps that cover recreational hotspots.
Most people live on one OS Explorer map because these also tend to align precisely with their neighbours. Overlaps exist, but they tend to be even more marginal than Landranger overlaps. You can find a jpg of Britain's OS Explorer maps here.
I live on one OS Explorer Map [162, Greenwich & Gravesend], but if I lived at the other end of Bow Road I'd also be on [173, London North]. The overlap in Bow is only one mile wide, whereas with Landrangers the overlap across central London spans three miles.
This is the Thames at Rotherhithe.
It's on three OS Explorer maps.
Being on three OS Explorer maps is rare, indeed in London it's unique.
The triple overlap includes the eastern side of the Rotherhithe peninsula as far south as Deptford dockyard, and also the western side of the Isle of Dogs at Millwall. It bulges slightly to the north so residents of Rotherhithe Street don't have to buy a north London map. The overlap marginally fails to include any stations but does include the river pier at Greenland Dock. The maps which overlap here are [173, London North], [161, London South] and [162, Greenwich & Gravesend].
Being on four OS Explorer maps is either extremely rare or non-existent. I haven't yet managed to find a four-way overlap anywhere in Britain, but I haven't scoured the map for long so you might have more luck if you lookyourself.
Update: Two of you have noted that four Explorer maps [OL4, OL5, OL6, OL7] overlap in the heart of the Lake District, but only across two grid squares in the hills west of Grasmere. The summits on all four maps are Calf Crag and Tarn Crag, both part of Wainwright's Central Fells.
This is the centre of Enfield.
It's on five Ordnance Survey maps.
Three Landrangers and two Explorers.
It's on three Landrangers for the same reason that Purley is, but this time on the northern side of the capital. The three Landrangers are [166 Luton & Hertford], [176, West London] and [177, East London].
It's on two Explorers because two of these maps overlap quite seriously up the Lea Valley, namely [173, London North] and [174, Epping Forest & Lea Valley].
Being on five of the Ordnance Survey's premier maps is really special, and this is quite a large area stretching from Crews Hill to Lower Edmonton. If you live here you can buy five maps with your street on, whereas I and most of the country can only buy two.
