It previously started at the Paradise Circus junction with the former Inner Ring Road (A4400) but originally ran along New Street in the city centre.

This route was completed in the 1960s, beginning with Quinton Expressway and resuming beyond the motorway junction as Manor Way (the Halesowen By-Pass).

Part of the historic Staffordshire/Worcestershire border runs along the road by Lightwoods Park, and today this is the boundary between Birmingham City Council and the Metropolitan Borough of Sandwell.

The road resumes its original route on the West side of Halesowen, entering Worcestershire and passing over the Clent Hills.

Continuing West, the road is entirely rural in nature, passing the Wyre Forest eventually meeting the A443 at a "T" junction.

However, the road was laid out, essentially in its present form (except where there are modern bypasses) by a series of 18th century turnpike trusts.

John Combe's 2008 book Get Your Kicks on the A456 (ISBN-10: 0955048206) documents the contributions made by musicians from the Kidderminster and Wyre Forest areas to pop and rock music between the mid-1950s and the 1970s, with reference to bands such as Chicken Shack and Led Zeppelin.