The A415 is a British A road which runs from the A4074 at Berinsfield

Berinsfield

Berinsfield is a village and civil parish in South Oxfordshire, about southeast of Oxford.-History:Palaeolithic and Roman artefacts were found during 20th century excavations to build the village. The Roman road between Dorchester-on-Thames and Alchester runs through the centre of Berinsfield...

, Oxfordshire

Oxfordshire

Oxfordshire is a county in the South East region of England, bordering on Warwickshire and Northamptonshire , Buckinghamshire , Berkshire , Wiltshire and Gloucestershire ....

  to Witney

Witney

Witney is a town on the River Windrush, west of Oxford in Oxfordshire, England.The place-name 'Witney' is first attested in a Saxon charter of 969 as 'Wyttannige'; it appears as 'Witenie' in the Domesday Book of 1086. The name means 'Witta's island'....

  passing through Abingdon

Abingdon, Oxfordshire

Abingdon or archaically Abingdon-on-Thames is a market town and civil parish in Oxfordshire, England. It is the seat of the Vale of White Horse district. Previously the county town of Berkshire, Abingdon is one of several places that claim to be Britain's oldest continuously occupied town, with...

, Marcham

Marcham

Marcham is a village and civil parish about west of Abingdon, Oxfordshire. It was part of Berkshire until the 1974 boundary changes transferred it to Oxfordshire.-Archaeology:...

 and Kingston Bagpuize

Kingston Bagpuize

Kingston Bagpuize is a village in the civil parish of Kingston Bagpuize with Southmoor, about west of Abingdon, Oxfordshire. It was part of Berkshire until the 1974 boundary changes.-Geography:...

. It crosses the River Thames

River Thames

The River Thames flows through southern England. It is the longest river entirely in England and the second longest in the United Kingdom. While it is best known because its lower reaches flow through central London, the river flows alongside several other towns and cities, including Oxford,...

 twice, at Abingdon Bridge

Abingdon Bridge

Abingdon Bridge consists of a pair of bridges across the River Thames at the town of Abingdon, Oxfordshire, England. It carries the A415 road from Abingdon to Dorchester, Oxfordshire – and crosses the Thames on the reach above Culham Lock, just below Abingdon Lock.The bridge is actually two...

 and Newbridge

Newbridge, Oxfordshire

Newbridge is a 13th century bridge carrying the A415 road over the River Thames in Oxfordshire, between Abingdon and Witney, close to the Thames' confluence with the River Windrush...

.

When UK roads were first classified in 1922, the A415 started at a junction with the A4 just west of Maidenhead

Maidenhead

Maidenhead is a town and unparished area within the Royal Borough of Windsor and Maidenhead, in Berkshire, England. It lies on the River Thames and is situated west of Charing Cross in London.-History:...

 in Berkshire

Berkshire

Berkshire is a historic county in the South of England. It is also often referred to as the Royal County of Berkshire because of the presence of the royal residence of Windsor Castle in the county; this usage, which dates to the 19th century at least, was recognised by the Queen in 1957, and...

. It ran through Henley-on-Thames

Henley-on-Thames

Henley-on-Thames is a town and civil parish on the River Thames in South Oxfordshire, England, about 10 miles downstream and north-east from Reading, 10 miles upstream and west from Maidenhead...

 and Benson

Benson, Oxfordshire

Benson is a village and civil parish in South Oxfordshire, England. It is about north of Wallingford at the foot of the Chiltern Hills at the confluence of a chalk stream and the River Thames, next to Benson Lock...

 to Shillingford

Shillingford

Shillingford is a hamlet on the River Thames in Warborough civil parish in South Oxfordshire, England. It lies on the main road between Oxford and Reading, at the junction with the A329.-History:...

 where it joined the then A42. It left the A42 a mile west at Dorchester

Dorchester, Oxfordshire

Dorchester-on-Thames is a village and civil parish on the River Thame in Oxfordshire, about northwest of Wallingford and southeast of Oxford. Despite its name, Dorchester is not on the River Thames, but just above the Thame's confluence with it...

. In the 1930s the section from Maidenhead to Shillingford became part of the A423

A423 road

The A423 road is a primary A road in England which leads from central Banbury to the A45 near Coventry. It starts in Banbury town centre as Southam Road and goes through the Southam Road Industrial Estate, then just north of Banbury it crosses over the M40, from there it passes close to several...

. It is now part of the A4130

A4130 road

The A4130 is a British A road which runs from a junction with the A404 at Burchetts Green, Berkshire to the A417 at Rowstock in Oxfordshire. It passes through Henley-on-Thames, and Nettlebed, and bypasses Wallingford and Didcot....

and the A4074.

In the 1980s, when the Dorchester Bypass was opened, the start of the A415 was switched to the western end of the bypass, at Berinsfield.