I posted a short message a while back about how the name of the chapter had been changed from being "Wikimedia Philadelphia" to "Wikimedia Pennsylvania", at the behest of the ChapCom. I received a very thoughtful reply from Kelly Martin about the post, and with permission I'm going to reproduce it here:
There are a number of points to consider with this, both pro and con. I would first like to point out that all previous chapters are being based off political boundaries, not organic social ones. Consider the case of the upcoming Wikimedia Canada chapter, where following a country boundary makes significantly less sense then having chapters for individual provinces. In fact the only other planned chapter that doesnt follow a national boarder is the Wikimedia Hong Kong, and it could be easily argued that Hong Kong has enough cultural and political autonomy that it isn't a far stretch from the rule.
One of the driving forces behind our chapter, and the reason why Johnny and myself are so interested in a chapter at all is because we want to do community outreach. We want to actually load up some people into a van, drive to a school or university or other group, and work with students and teachers and community members. It was this idea of a close-knit community program that initially had us interested in a community chapter: Philadelphia. Being "Wikimedia Philadelphia" had the advantage of specificity: It describes exactly where the chapter is centered, and where it is legally incorporated. However, it has the disadvantage that many people who would be interested in joining a local chapter are not exactly in the Philadelphia region. "Wikimedia Delaware Valley" would perhaps have been a little better, but then it's ambiguous where the chapter is headquartered.
As the chapter gets too large, we lose the ability for our members to congregate, and to work in close physical proximity when such work is required. People from California are likely to be working on very different community outreach projects then are people from Pennsylvania. Beyond that, there is very little chance for collaboration between the two groups, except for the occasional encouragement over long-distance communication lines.
As the area gets larger, the ability for members to come together, for work projects or annual meetings, or whatever, decreases. Even if we did a "Mid-Atlantic Region" chapter, it would be difficult for all the members to participate equally. There would also be an impetus for the center of activity to be pulled away from the geographical center. For instance, more users from New York would want the meetings and activities to be held in New York, and users from the Baltimore-Washington area would want to pull focus down to that location. What we end up with is members who are either disenfranchised (not being able to attend events that are occurring at the opposite end of our geographical area), or else we end up with multiple discordant efforts (some people in newyork, some in baltimore, some in philadelphia, etc).
Even "Wikimedia Pennsylvania" has the problems that it includes Philadelphia and Pittsburg (which are separated enough to make much collaboration infeasable) while at the same time essentially excluding people who really can belong in it: Trenton, Camden, Wilmington, etc. However, we have tried to overcome this hurdle by not placing residential restrictions on members.
There is probably a lot more to say about this issue, but i'll cut the discussion off here. At the moment, we've done so much set-up work under the name "Wikimedia Pennsylvania" that any change would be difficult. Some of the people who are working hardest on the idea really see "Pennsylvania" as being a good compromise between big and small, so that's what we are going to run with.