As to Maurices point about it being a "hidden gem", the Conservancy that runs that area actually have been considering closing it due excessive foot traffic and continued parking issues on the surrounding streets.
It has been on my list to fish for about two years but I have not done due largely to this article :
http://lancasteronline.com/opinion/editorials/alternatives-to-tucquan-glen/article_9b7e5880-3230-11e5-aa21-d34214fdc79a.html
so before you all rush down there, can I suggest a mid week visit or perhaps in bad weather ? even better, fish above the glen.
to me knowledge it was not stocked since 2003 and does hold both resident and transitional fish that summer over in the depths of the Susky.
cheers
Mark.