Ponterwyd Old Bridge is a road bridge over the Afon Rheidol, probably built in the later 18th century. A new bridge to the south was built when the new turnpike road to Llangurig was built in 1812. The old bridge's narrow humped profile makes it one of the most distinctive bridges of the county. Built of rubble stone, it has a fine broad single arch, 15.5m span, with stone voussoirs and a thin crown to the arch. The rubble parapets have end-on stone copings, each side of narrow roadway of 2.4m width.

Reference:
Cadw listed buildings database.
RCAHMW AP955046/51