The A422 is an "A" road for east–west journeys in south central England, connecting the county towns of Bedford and Worcester by way of Milton Keynes, Buckingham, Banbury and Stratford-upon-Avon.

Passing over the M1, it crosses through the northern part of the Milton Keynes urban area as a dual carriageway, known locally additionally as the H3 Monks Way grid road.

Upon meeting the A5 in Milton Keynes, the A422 multiplexes northbound with it for 3 miles (4.8 km) as far as Old Stratford in Northamptonshire where it regains its identity (and single carriageway status).

From the A422/B4525 roundabout, on the western edge of Middleton Cheney (east of Junction 11), the road is dualled until it meets the A423 and resumes as a single carriageway.

From there to Stratford-upon-Avon, it is a minor road crossing into Warwickshire at the Battle of Edgehill site, where it descends steeply down the Sunrising Hill escarpment and then across the Fosse Way.