JohnJav, that is a hell of a watershed brown trout on a fly. For me, the East Branch is a really good RAINBOW fishery, but never got a brown over 18 or so there
C Falls outlet (that first legal area below the dam), and CFalls Inlet (aka the WB outlet) have some nice brownies, especially in the Fall, when the spawners come up (but you can only legally fish until 9/30)
I have never fished the Croton River (New Croton outlet to the Hudson River), but years ago some fly fisher told me there are very big browns in there That river is a weird one - at times, you can catch a herring, a striper, a carp, who knows?
You should try using the fly rod on Croton Falls in the Spring I have tried, but never hooked up with a big one, although I've gotten smaller browns I had the jolt of my life two years ago, when I was casting a sawbelly pattern near the stoneleigh "viaduct" and a big brownie followed it up to the boat Definitely a double digit fish, but he just bolted when he realized it was a fake