Service status:
We're okay :)

This tool returns the Watsonian vice-county (or vice-counties) that the grid reference contains (see http://en.wikipedia.org/wiki/Vice-county for more information on vice-counties). It is accurate to 100m (although by the nature of the data down to 1m accuracy is available where the 100m grid square contains a single vice-county) and works with tetrad (e.g. SE45Y) and 5km grid references (e.g. SE45NW) as well as 1km, 10km and 100km grid references.

There are currently no plans to include the Praeger vice-counties of Ireland – I’m not aware of any similar boundaries being available to create the necessary data. Correct me if I’m wrong and I may look into it.

This tool as a web service:

To call the service (currently without charge or restriction; if you’re planning on hammering the service, please let me know in advance – whilst I don’t charge, Google does!), use a URL of the following format:

http://grid2vc.cucaera.co.uk/?r=<gridref>&f=<format>

where <gridref> is a grid reference or list of grid references seperate by a comma and <format> is one of JSON, XML, TEXT or left blank for “pretty” HTML output with the actual vice-county names (as used above).

The web service makes no attempt to notify or correct invalid grid references – it simply returns nothing if no match is found.

Examples:

JSON
URL: http://grid2vc.cucaera.co.uk/?r=SU1561&f=json
Returns: [7,8]

XML
URL: http://grid2vc.cucaera.co.uk/?r=SU1561&f=xml
Returns: <data><vice-county>7</vice-county><vice-county>8</vice-county></data>

TEXT
URL: http://grid2vc.cucaera.co.uk/?r=SU1561&f=text
Returns: 7,8

“pretty”
URL: http://grid2vc.cucaera.co.uk/?r=SU1561
Returns: VC7 North Wiltshire<br />VC8 South Wiltshire

The information is based on data provided by the NBN. Contains Ordnance Survey data © Crown copyright and database right 2012.

If you interested in the mechanics behind the web service, it’s basically just a large (very – over 3.5 million data points) lookup table containing grid references and their vice-counties hosted by the Google App Engine with the script behind the scenes written in Python. A little optimization is done in that those grid references whose “parent” grid reference contains 100% of one vice-county can be assumed to be the same vice-county, and memcache is used to store recent queries, but that’s about as complicated as it gets.

View the vice-county boundaries

1 West Cornwall with Scilly 2 East Cornwall
3 South Devon 4 North Devon
5 South Somerset 6 North Somerset
7 North Wiltshire 8 South Wiltshire
9 Dorset 10 Isle of Wight
11 South Hampshire 12 North Hampshire
13 West Sussex 14 East Sussex
15 East Kent 16 West Kent
17 Surrey 18 South Essex
19 North Essex 20 Hertfordshire
21 Middlesex 22 Berkshire
23 Oxfordshire 24 Buckinghamshire
25 East Suffolk 26 West Suffolk
27 East Norfolk 28 West Norfolk
29 Cambridgeshire 30 Bedfordshire
31 Huntingdonshire 32 Northamptonshire
33 East Gloucestershire 34 West Gloucestershire
35 Monmouthshire 36 Herefordshire
37 Worcestershire 38 Warwickshire
39 Staffordshire 40 Shropshire
41 Glamorganshire 42 Breconshire
43 Radnorshire 44 Carmarthenshire
45 Pembrokeshire 46 Cardiganshire
47 Montgomeryshire 48 Merionethshire
49 Caernarvonshire 50 Denbighshire
51 Flintshire 52 Anglesey
53 South Lincolnshire 54 North Lincolnshire
55 Leicestershire (with Rutland) 56 Nottinghamshire
57 Derbyshire 58 Cheshire
59 South Lancashire 60 West Lancashire
61 South-east Yorkshire 62 North-east Yorkshire
63 South-west Yorkshire 64 Mid-west Yorkshire
65 North-west Yorkshire 66 County Durham
67 South Northumberland 68 North Northumberland
69 Westmorland (with Furness) 70 Cumberland
71 Isle of Man 72 Dumfriesshire
73 Kirkcudbrightshire 74 Wigtownshire
75 Ayrshire 76 Renfrewshire
77 Lanarkshire 78 Peebleshire
79 Selkirkshire 80 Roxburghshire
81 Berwickshire 82 East Lothian
83 Midlothian 84 West Lothian
85 Fifeshire 86 Stirlingshire
87 West Perthshire 88 Mid Perthshire
89 East Perthshire 90 Angus
91 Kincardineshire 92 South Aberdeenshire
93 North Aberdeenshire 94 Banffshire
95 Moray 96 East Inverness-shire
97 West Inverness-shire 98 Argyllshire
99 Dunbartonshire 100 Clyde Isles
101 Kintyre 102 South Ebudes
103 Mid Ebudes 104 North Ebudes
105 West Ross & Cromarty 106 East Ross & Cromarty
107 East Sutherland 108 West Sutherland
109 Caithness 110 Outer Hebrides
111 Orkney 112 Shetland