A trunk road is a major highway with a specific legal classification in some jurisdictions, notably the United Kingdom, Sweden and formerly Ireland.

Many trunk roads have segregated lanes in a dual carriageway, or are of motorway standard.

The Trunk Roads Act came into force in England and Wales on 1 April 1937, and in Scotland on 16 May 1937.

This development did not extend to Northern Ireland, which has always had a separate system of highway and road traffic law.

The Welsh Government has had responsibility for trunk roads in Wales since its establishment in 1998.

National Highways publishes a full network map of trunk roads and motorways in England.

In England, the government has de-trunked much of the trunk road network since the late 1990s, transferring responsibility to local councils to allow National Highways to concentrate on a selection of core trunk routes, mostly dual carriageways and motorways.

[citation needed] They are considered recommended main roads for long-distance traffic.

They were also supposed to be used for movement and transport of heavy military vehicles, ordnance and logistics and during wartime were to be guarded and defended at all odds.

National Roads 73 and 75 are both built to motorway standard and have high traffic, but are not considered trunk.

However, individual states are responsible for actual highway construction and maintenance, even though the federal government helps fund these activities.