M1 / A45 near Northampton A14 in Kettering The A43 is a primary route in the English Midlands and northern South East England, that runs from the M40 motorway near Ardley in Oxfordshire to Stamford in Lincolnshire.

[citation needed] Following the junction with the M40, the A43 first meets a roundabout with the B4100 for traffic headed north-west for the village of Aynho or south for the town of Bicester.

Continuing north, the A43 passes many Oxfordshire and Northamptonshire rural villages and towns before meeting the A421 which spurs towards Buckingham and later, Milton Keynes.

Two miles north of Brackley, the B4525 (a B classified route for traffic from South Northamptonshire to reach the M40 at Banbury) joins the A43.

From here, the A43 leaves the Oxfordshire borders and continues in a north-easterly direction towards Silverstone, where the road joins the A413 at a grade-separated junction.

[3] Continuing towards Northampton, it by-passes Blisworth and Milton Malsor villages, before reaching the M1 at junction 15A, at Rothersthorpe services.

The old road is still regularly used, possibly due to poor signage or lack of SatNav updates.

A new bypass, called the Corby Link Road, opened in 2014, from Barford Bridge on the A6003 to the A43 west of Stanion.

When the M40 was opened in 1991 the road from the Pear Tree Roundabout to Weston-on-the-Green was renumbered A34, and the stretch through Middleton Stoney between the A34 and junction 10 of the M40 was downgraded to the B430.