A509 road

For the road from Enniskillen to the border with the Republic of Ireland, see A509 road (Northern Ireland).

A509
Major junctions
North end	Kettering 52.3880°N 0.7147°W / 52.3880; -0.7147 (A509 road (northern end))
Major intersections	A14 (J9) A45 A428 A422 M1 (J14) A4146 A5
South end	Milton Keynes 52.0374°N 0.7819°W / 52.0374; -0.7819 (A509 road (southern end))
Location
Country	United Kingdom
Primary destinations	Kettering, Wellingborough, Milton Keynes
Road network
Roads in the United Kingdom Motorways A and B road zones
← A508 → A510

The A509 is a short A-class road (around 30 miles (48 km) long) for north–south journeys in south central England, forming the route from Kettering in Northamptonshire to the A5 in Milton Keynes, via M1 J14.

From north to south, the road begins at Wicksteed Park in the outskirts of Kettering. It then crosses the A14 (where it becomes a primary route) and goes through Isham and Great Harrowden. After this it goes on to form the Wellingborough western bypass before leaving Northamptonshire to cross into the City of Milton Keynes (and Buckinghamshire). From there, it crosses the A428 at a roundabout and cuts through the centre of Olney. South of Olney the road passes Emberton, meeting the A422 just north-east of Newport Pagnell, where the routes multiplex to form the Newport Pagnell eastern bypass. South of Newport Pagnell, the routes diverge at a roundabout with the A509 turning south and the A422 continuing westbound. Here the A509 is a single carriageway once more until it crosses the M1 at Junction 14, where it enters the 1967 designated area of Milton Keynes and (at another roundabout) the existing southbound route becomes part of the A4146 (here, the A4146 takes over the 'primary route' designation and the A509 loses it). Continuing westwards from here, the road once more becomes a dual carriageway, running for a further 4 miles (6.4 km) past the edge of Central Milton Keynes (the central business district) and the Network Rail National Centre ('Quadrant:MK'), to link up finally with the A5. Through Milton Keynes, the road is known as the H5 Portway.

Proposed Isham bypass

The A509 Isham Bypass is a proposal by North Northamptonshire Council to improve transport links between Kettering and Wellingborough, to improve access from Wellingborough to the A14, and to remove 'through traffic' from Isham village.

A bid for Major Road Network funding was submitted to the Department for Transport in March 2020, with a Strategic Outline Business Case in December 2020. In October 2021, £1.859m of funding from the Department of Transport was secured towards the next stages of developing the proposals for the bypass. A full planning application is due to be submitted by January 2023.