Quaker Study Centers in the US (yes, more than one!)

I keep hearing about "Pendle Hill, the Quaker study centre in the US." 

I hardly ever hear anyone say, "Pendle Hill, one of the Quaker study centres in the US."   I don't think I've ever heard anyone here talk about any of the others (except in our house). 

I realize Friends here may be familiar primarily with Pendle Hill, but there really are others; so I thought it might be useful to post what some of them are. 

Off the top of my head, I came up with six, and that was without thinking about it very hard.  Thinking some more, doing a little research, and posting to social networking about it, I got three others. 

Granted, I'm not making a huge distinction between "study centers," "retreat centers," and "conference centers," especially since there's a lot of overlap; but I promise, more than one of these are "Quaker study centers."

Here's my list; I'm sure there are more: 

• Pendle Hill (PA): http://pendlehill.org/
• Powell House (NY): http://www.powellhouse.org/
• Ben Lomond Quaker Center (CA): http://www.quakercenter.org/
• Woolman Hill (MA): http://www.woolmanhill.org/
• Quaker Hill (IN): http://www.qhcc.org/ 
• Burlington Conference Center (NJ):  http://www.pym.org/burlingtonconference/ 
• Friends Wilderness Center (WV): http://www.friendswilderness.org/home0.aspx
• William Penn House (DC): http://williampennhouse.org/
• Michigan Friends Center (MI): http://mfcenter.org/ 

(And I'm not even including a whole raft of Evangelical conference and retreat centers which operate as camps during the summer.)