Route of a Roman Road
340 Devizes Road (image) has a link to Old Sarum and Stratford sub Castle. It lies over the Roman road from Old Sarum and the Roman settlement of Sorviodunum to Dorchester, or today from its route from the junction of Castle Keep and Stratford Road to Folly Lane. 
This was the Portway that runs under the Salisbury Council Football Field in Stratford sub Castle and not the track to its south east so named now that joins the Stratford Road at Farthing cottage and Portway Lodge and runs up alongside Hudson’s Field.
The term Portway is sometimes applied to the Sarum to Silchester route, sometimes the whole Dorchester to Silchester route and to this roughly parallel track. A building at least 6 m wide lay perpendicular to this road where 6 Castle Keep now stands. [2 ]
The road crossed the river at the nose of Tadpole Island (perhaps it was a two-stage crossing). David James, village resident and Romanist, has reported Roman finds either side of the road line north east of Cowslip Farm (which in 1900 was Coldharbour Farm)  and a copy of one of his articles about The Portway appears on this website. 
The road into the Salisbury and South Wilts Golf Club from the Netherhampton Road is the same route.
The Chester or Ceaster of Silchester and Dorchester means a Roman Castrum, a military camp or fort.
There are other Portways in England eg Derbyshire, Birmingham, Wye Valley. But not all mean antiquity. In Bristol it is a 20th C road to the port.
The course of the (Roman) Portway from the river crossing to Folly Lane can be seen in this 2020 aerial view.
Map data ©2020 Google
Ordnance Survey Wiltshire LXVI.SE Revised: 1900 Published: 1902
Ordnance Survey Wiltshire XVI.SE Revised: 1923 to 1924 Published: 1926
Maps Reproduced with the permission of the National Library of Scotland
Ordnance Survey Wiltshire LXVI.SE Revised: 1938 Published: ca. 1946
 Bill Moffat in appendix to Settlement in the Hinterland to Sorviodunum David James 2010 Wiltshire Archaeological and Natural History magazine 103 p172
 James, D. The Portway, Stratford sub Castle. https://www.stratfordsubcastle.org.uk/the-portway