The longest roads and highways in the world, ranked by length

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The record table

Road lengths are route lengths as designated, not driving distances, and the longest routes are the hardest to state precisely: designations change, spurs are added, and a route may be interrupted. Where a figure is disputed the note records why.

How this archive measures: lengths, bores, dates and ordering

How this table is compiled

The unit matters as much as the number: a figure in feet and a figure in metres are routinely mixed up in secondary sources. Records in this class move whenever one large scheme opens, and a page that is not re-checked drifts out of date without saying so. Height is measured above mean sea level.

Every figure below is traceable to a named source. Where a record is contested the table states both the figure and the reason for the dispute, instead of picking a winner silently. Corrections have historically arrived by letter rather than by form, and that is still the way most errors in it have been found.

This table records the longest roads and highways in the world, part of an infrastructure archive kept here since the late 1990s. The table is short because the sourcing bar is high. Opening dates refer to the date traffic was admitted, not to the completion of construction, which normally falls a year or two earlier.

A tunnel either exists or it does not; a route can gain three hundred kilometres because a ministry renumbered a corridor. Ranking is by the figure named in the header, nothing else. Renaming is common on long routes, so a designation in the table reflects the name in use at the time of recording.

Road route lengths are the least precise figures in this archive, and the longest routes are the least precise of all. Driving distance is not route length: a route length is measured along the designated alignment, not along the shortest practical journey. A record is a claim about a definition as much as a measurement.

Reading the figures

Geology and terrain decide cost and programme far more than distance does, on a road as much as in a bore. Superlatives attract dispute because they are the figures most often quoted without their qualifications attached. Comparing one country's figure against a neighbour's is more informative than reading either alone, because designation practice differs sharply across borders.

Part of the reason is that a road is a designation rather than an object, and designations are administrative decisions. The Trans-Canada Highway is firmer at 7 821 kilometres because it was designed as a single project from the outset. Metres are used for structures and kilometres for routes, matching the units the responsible administrations publish.

Australia's figure is unusual in being both very large and well defined, which is why it heads the national-highway class. Those two are often conflated, and the difference is a matter of designation rather than of tarmac. The archive began as a private compilation and grew through correspondence with engineers and administrations in more than twenty countries.

A record table is a snapshot with a date on it, which is the only honest way to publish one. Figures are compiled from operator publications, national administrations and the engineering press, and checked against one another. A superlative is only as good as its definition, and most disputes in this field are definitional rather than factual.

The longest-road question is asked more often than any other in this archive and has the least stable answer. A designation can be extended, rerouted or renumbered without any construction taking place, which changes the published length overnight. The note column carries the qualifications, and on record tables the qualifications are usually the interesting part.