Grove Park Interchange is junction 25A of the M4 in Newport, Monmouthshire. It came into being as a result of the Brynglas Tunnels and Malpas Road Relief scheme. As a result of that scheme, the primary A4042 was rerouted from Malpas Road onto a new alignment, partially following the old Monmouthshire Railway eastern valleys line. Where this route crosses the eastern mouth of the Brynglas Tunnels, a new roundabout was built (known as Grove Park Roundabout, along with sliproads connecting directly to the existing J25, which was then made limited-access. The intention was to prevent traffic from J25 travelling westbound through the tunnels, instead forcing them into a detour either to the north or south to gain access at J26 on the other side of Brynglas Hill.