Black Rock & Leatherman's Cave
(Not sure if this is usual, or because of the holiday weekend, but there wasn't much parking left at the end of Northfield Road even though it was only 8am. The reservoir here is clearly a very popular fishing spot. The lot was still full, albeit with different cars, when we left around 3pm. There are plenty of other places to park, but they will lead to a slightly longer walk depending on where you end up. As we got ready to head out we saw a couple people leaving, each with several fish in tow, too, so must be popular for good reason.) :)
It was an absolutely beautiful day for it, hiking, or fishing.
This is definitely one hike you want to do on a sunny day. The Mattatuck is fairly rugged, with lots of open rocky-ridge that could be slippery in wet or snowy conditions. There were several stream crossings as well.
We were definitely glad we hit this view first as we passed a lot of people heading up from Black Rock State Park when we were heading back down.
We spent a decent amount of time exploring the cave and taking pictures. It was pretty cool, a few tight squeezes getting in and through the cave. After you leave there is another rocky area you'll come on with a choice of tight squeeze or a climb to get through, then you can be on your way. :)