Road Facts and Figures

This page is an attempt to provide details of the longest, highest, etc classified roads in the British Isles. References to 'GB' below exclude Northern Ireland, which is treated independently.

This page is still a 'work in progress' and updates / corrections are more than welcome.

'Motorable Roads'

According to the Ordnance Survey, there are approximately 321,000 miles of 'motorable', roads in the UK. The precise definition of this is unclear, but probably relates to public highway suitable for/passable by motor vehicles.

Longest Road

Non Motorways

The A1 is the longest classified Road in GB at 396 miles from London to Edinburgh.
The A38 is the longest 2-digit A-road in GB at over 309 miles from Bodmin to Mansfield.
The A361 is the longest 3-digit A-road in GB at 195 miles from Ilfracombe to Kilsby.
The A1101 is the longest 4 digit A-road in GB at 53.4 miles from Long Sutton to Bury St Edmunds.
The B6318 is the longest B-road in GB at 61.4 miles from Heddon-on-the-Wall to Langholm.

However, none of the A-roads are continuous as they either have a non-dominant multiplex, or motorway (eg A1(M)) sections, or both.

The longest A road wholly in England is the A38.
The longest A road wholly in Wales is the A470 at 185 miles, closely followed by the A487 at 174 miles.
The longest A road wholly in Scotland is the A9 at 279 miles, with the A82 coming a distant second at 175 miles, and the A836 is the longest 3-digit route at 125 miles.

A roads over 100 miles

Rank	Number	Distance	Rank	Number	Distance
1	A1	396 miles	21	A90	148 miles
2	A38	309 miles	22	A52	146 miles
3	A30	284 miles	23	A14	137 miles
4	A6	282 miles	24	A4	130 miles
5	A9	279 miles	25	A12	129 miles
6	A5	270 miles	26	A832	126 miles
7	A40	256 miles	27	A836	125 miles
8	A41	222 miles	28	A19	124 miles
9	A46	205 miles	29	A57	122 miles
10	A39	204 miles	30	A48	119 miles
11	A34	199 miles	31	A259	117 miles
12	A361	195 miles	32	A66	115 miles
13	A470	185 miles	33	A85	115 miles
14	A47	179 miles	34	A11	110 miles
15	A90	178 miles	35	A61	107 miles
16	A82	175 miles	36	A59	106 miles
17	A487	174 miles	37	A449	105 miles
18	A10	161 miles	38	A838	104 miles
19	A49	158 miles	39	A27	103 miles
20	A483	155 miles	40	A96	102 miles
			41	A614	100 miles

The longest N road in Ireland appears to be the N59
The longest A road in Northern Ireland is the A2

Motorways

The M6 is the longest Motorway in GB at 236 miles from Catthorpe, Leicestershire to the Scottish Border.
The M25 is the longest 2-digit Motorway in GB at over 117 miles from Dartford to Thurrock.
The M180 is the longest 3-digit Motorway in GB at 25 miles from Hatfield, Yorkshire to Barnetby-le-Wold.
The A1(M) is the longest Ax(M) road in GB at 122 miles from South Mimms to Washington in five sections while the A74(M) is the longest continuous Ax(M) Motorway, running from Abington to just south of Gretna Green.

The longest Motorway wholly in England is the M6. Its 236 miles stop just short of the Scottish Border.
The longest, and only, Motorway wholly in Wales is the A48(M) at 2 miles.
The longest Motorway wholly in Scotland is the M8 at 61 miles, with the M9 coming second at 51 miles.

The longest motorway in Ireland is, for now, the M7 at a distance of 186.6 km (116 miles).
The longest motorway in Northern Ireland is the M1 at 38 miles.

Highest Road

The highest classified road in Scotland is probably the Lechd Summit on the A939, at 2113' (644m). Other high routes in Scotland include the Bealach na Ba pass in Applecross, which reaches 2054' (626m), and the Cairngorm Mountain road off the B970, which reaches approximately 2100' (640m).

Shortest Road

There must be many claimants for the title of shortest classified road in GB. Most are urban link roads, which were allocated separate numbers many years ago, whereas these days they would simply be a spur of the main route.

A Roads less than approx. 500yds/m long include:

B Roads less than approx. 500yds/m long include:

Roads meeting each other more than twice

There are many examples of two roads meeting each other again and again. Generally they result from a main route being realigned, and the old road being downgraded to a lesser status. If the two routes multiplex with each other, both junctions are counted. Some examples are:

A48 / M4 Meet each other about 10 times in total as they weave through South Wales.
A38 / M5 Meet each other 8 times directly, and many more times via a very short stretch on another route to get to the junction (eg J23, Bridgwater, where the A39 provides the link).
A830 / B8008 have 8 junctions with each other (including spurs) between Arisaig and Mallaig.
A1/A199 have 6 junctions with each other (including spurs) between Brunstane and Dunbar. One of the junctions is a cannon.

North, South, East and West Extremities

Geographical Entities

Area	North	South	East	West
British Isles	B9087	A3112	A12	R559
Great Britain	B9087	A3112	A12	A888
Ireland (island)	R242	R591	A2	R559
Mainland GB	B855	A3083	A12	B884

Political Entities

Area	North	South	East	West
UK	B9087	A3112	A12	A46 (NI)
England	A1	A3112 (on mainland A3083)	A12	A3111 (on mainland A30)
Northern Ireland	B15	B27	A2	A46
Scotland	B9087	B7041	B9088 (mainland B9018)	A888 (mainland B884)
Wales	A5025	A4055	M48 (A466 is easternmost non-motorway)	B4583
Republic of Ireland	R242	R591	R750	R559

Motorways (note junction references are given to the nearest junction to the extremity)

Area	North	South	East	West
British Isles	M90 spur to A9	M5 j31	M20 j13	M8 (RoI)
GB	M90 spur to A9	M5 j31	M20 j13	M4 j49
Ireland (island)	M2 (NI)	M8 (RoI)	M5 (NI)	M8 (RoI)
UK	M90 spur to A9	M5 j31	M20 j13	M2 (NI)
RoI	M1	M8	M11	M8
NI	M2	M12	M5	M1
Wales	M4 j49	M4 j33	M48 j2	M4 j49
Scotland	M90 spur to A9	A74(M) border	M90 j9	M8 j31
England	A74(M) border	M5 j31	M20 j13	M5 j31

M roads by zone (note junction references are given to the nearest junction to the extremity)

Starting Number	North	South	East	West
1	M1 j48	M1 j1	M11 j8	M1 j40
2	M25 j21	M275	M20 j13	M27 j1
3	M32 southern end	M3 southern end	M3 j1	M32
4	M42 j11	M4 j11	M4 j1	M4 j48
5	M55 j3	M5 j31	M5 at M6	M5 j31
6	M6 j45	M6 at M1	M62 j38	M62 j4
7	M73 j3	M74 j13	M74 j13	M77 j8
8	M80 j6	M8 j6	M8 j1	M8 j31
9	M90 spur to A9	M9 j1	M9 j9	M9 j11

A roads by zone

Starting number	North	South	East	West	Furthest 'wrong way' strayer	Furthest 'right way' strayer
1	A198	A1089	A12	A1	A100	A14
2	A219	A259	A255	A27	A27	A282
3	A34	A3112	A3211	A3111	A34	A3023 (never enters zone, A31)
4	A49	A4	A47	A487	A47	A4174
5	A595	A5	A52	A5154	A59	A51
6	A6137	A6129	A603	A66	A64	A66
7	A770	A716	A7	A77	A706	A720
8	A836	A83	A836	A888	A823	A899
9	A968	A902	A968	A9	N/A	A949

B roads by zone

Starting Number	North	South	East	West
1	B1346	B189	B1345	B1350
2	B205	B2145	B2052	B2177
3	B3028	B3296	B300	B3315
4	B4546	B4640	B400	B4583
5	B5307	B524	B502	B5109
6	B6370	B6424	B660	B6357
7	B788	B7041	B7060	B738
8	B855	B842	B874	B888
9	B9087	B900 or B901 (to close to call)	B9088	B9164

Sources

Extremities thread on SABRE forum

T1(M)'s word document

Other Miscellaneous Facts

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