Walking the Thresholds and its autumnal cousin in September,
Crossing the Thresholds, are both held in Pennsylvania, at Four Quarters Farm. (It's very near the Maryland border, but not actually in Maryland.)
There is also
Dancing the Endless Dream in Texas over Memorial Day weekend and this year a new (or new-public, anyway) one on Labor Day weekend called
A Gathering Echo, which might be more accessible than the west coast. Also,
KinSouth Swamp Gather in Florida, but I don't know if that's going on this year (the dates haven't changed from the 2008 info).
Formerly known as Eshari.
arethinn @ tumblr and Dreamwidth | shyfoxling @ DeviantArt