what is sleepy hollow ?

I'm not sure specifically what you want to know here. The town of Sleepy Hollow is in upstate New York. As for the story, here is a brief synopsis taken from this very site,

“The Legend of Sleepy Hollow” tells the story of Ichabod Crane and his hapless attempt to win the heart and hand of Katrina Van Tassel in the context of a comical ghost story. Ichabod comes to Sleepy Hollow, New York, from his home state of Connecticut, to be the schoolmaster of the village. Sleepy Hollow is a small, very quiet town said to be under some kind of enchantment."

Then we get into the headless horseman thing but I think this should suffice for now. For more information check out my source link below.