San Cristobal Canyon is the only volcanic rift in Puerto Rico and is approximately 650 feet down to the bottom. The temperature at the top is considerably cooler than down in the canyon. The canyon is about 9 kilometers long. There are two rivers running through it and several waterfalls. It isn't easy to see. There is no built 'Tourist' access road, it is just there. It is located about half way between Barranquitas and Aibonito. Lovely and cool at the top, it is much warmer at the bottom.

Access is off #725 on the south side and also around the north side there are several access and one along the western side.

La Piedra Restaurant sometimes sponsors hikes into it and Felix, a guide, often takes people on a Saturday. It is not an easy climb into the canyon and back out again, but it is relatively easy to just gaze into it. For the more adventurous and in shape it's a great days exploration.