The B5419 is a largely urban road in south Lancashire. Originally numbered A568 the road gained its present number following the construction of the A557 Widnes bypass.
The road starts at a roundabout on the A569 and B5204 just south of Lea Green station. We head south along a residential road through the St Helens suburb of Clock Face, then pass a reclaimed colliery site to enter open fields and cross the M62. A straight run across the fields takes us to traffic lights on the A57 (which links to M62 J7), after which we cross the A557 at a southeast-facing GSJ (traffic wanting to head northwest should have taken the A57).
After a couple more fields we reach a T-junction on the A5080 and multiplex along it briefly to the right to a roundabout where we turn left to regain the B5419 number. We now head south through the Widnes suburb of Farnworth, presently reaching Widnes station (although we're still a way from the town centre). A short distance further on the road becomes dual (this would have been D2 originally but much of the carriageway is now taken up by cycle lanes making the road D1); we continue south through the suburbs along Kingsway into the town centre and reach a roundabout.
The A568 continued ahead here but we bear right onto a road that is still D2. We pass industrial estates and end when we merge into the A562 just east of that road's junction with the A533, which is being rebuilt as part of the Mersey Gateway Bridge works.