Re: Fly fishing spots near Washington, DC
The Gunpowder river offers year-round WILD brown trout fishing about 1.5 hours from DC. I went yesterday and caught 6 or 7 browns in about 3 hours. They are mostly 6-10 inches but there are plenty of fish 14" and up if you have some luck. There is a shop there called Backwater Angler, they'll point you in the right direction.
If you simply check the Maryland DNR, they list stocked streams with dates.