Lledan Brook Aqueduct
This is my first Montgomery Canal Aqueduct, and so a new label!
I can't claim to have bagged this one myself but fortunately I have friends out there that know of my odd interest in Aqueducts, and will take photos for my benefit. Credit for these one goes to Halfe who has published a full post of the structure on his blog.
This is the second aqueduct on the site, the first being a masonry affair later replaced with an iron trough dressed up to look like masonry. The sign board explains all: