I visited the Monmouthshire and Brecon canal in September 2009 during mixed weather. The canal is typified by the photo on the left (click to enlarge), but also has superb views over the River Usk and beyond to the Black Mountains. I covered the stretch North from Pontypool, a distance of about 33 miles with only 6 locks 5 of which are close together at Llangynidr. There are many picturesque and interesting features  along the route with a number of drawbridges and some of the loveliest stone bridges I have seen anywhere on the network. Characterful canal side pubs are in abundance.

The limit  of navigation is a further 2 miles South of Pontypool at the start of Five Locks. The canal is, of course, isolated at the moment but at one time it continued down to Newport Docks. There is another branch, the Crumlin Arm, which goes 7 miles West from Newport to Pontywaun. Restoration is underway on a number of stretches.

Here is a slideshow of what I saw on my journey.

Below is a Google map of the route. The waymarks follow the sequence of the slideshow.