The Dartford - Thurrock River Crossing, Dartford River Crossing (DRC) (or simply the Dartford Crossing) is a major road crossing of the River Thames in England, connecting Dartford in the south to Thurrock in the north, via two road tunnels and the Queen Elizabeth II Bridge. It opened in stages, the west tunnel in 1963,[1] the east tunnel in 1980,[1] and the bridge in 1991. Until the opening of the bridge, built to the east of the two tunnels, the crossing was known as the Dartford Tunnel.

The two tunnels are 1,430 m (1,560 yd) long,[1] while the cable-stayed bridge is 137 metres (449 ft) high with a main span of 450 metres (490 yd).[2] The crossing carries nearly 150,000 vehicles a day and forms part of London's orbital route, the M25—although the crossing and its approach road are actually the A282, allowing traffic prohibited from motorways to use the crossing. Southbound traffic crosses the four lane bridge; northbound traffic uses both of the two lane road tunnels. However, in bad weather or high winds, the bridge is closed and the crossing reverts to using the tunnels for both directions.

The crossing is 16 miles (26 km) east of the centre of London, but just 2 miles (3.2 km) outside the Greater London boundary. Its southern end is in Dartford, Kent; while its northern end is in Thurrock, Essex. Formerly managed jointly by Kent and Essex county councils, the crossing is now managed by Connect Plus (M25) Limited on behalf of the Highways Agency.

The crossing is a major bottleneck in the regional road network, being the easternmost crossing of the River Thames, and the only road crossing east of London. Therefore, the crossing is subject to major traffic congestion and disruption in the event of accidents or bad weather. The next nearest road crossings to the west are the Woolwich Ferry and the Blackwall Tunnel, both well within East London. The proposed Thames Gateway Bridge between these two crossings and the Dartford crossing was given planning permission in December 2004, but was later cancelled in November 2008.[3] The Lower Thames Crossing is a tentative proposal for a crossing, most likely a tunnel, to the east of the Dartford crossing.

In October 2009, the Government announced its intention to sell the crossing as part of a public sector deficit reduction strategy