Section of Sarn Helen measuring approximately four miles from Llanio-Isaf in the south to Tyncelyn (NPRN 413964; NPRN 403445) in the north, along what is now the B4578. Llanio was the site of Bremia Roman settlement (NPRN 303530; NPRN 92319), and Sarn Helen road continues south from Llanio-Isaf to Carmarthen (NPRN 309268). The section of Sarn Helen Roman road from Llanio-Isaf to Tyncelyn was photographed by Dr Toby Driver during the Royal Commission's programme of archaeological aerial reconnaissance on 30th June 2015.
M. Ryder, RCAHMW, 21st January 2019