Hi and welcome to the neighborhood! We hs our 7 year old and 4 year old. The groups I'm familiar with are THEA....which has many crunchy and some not so crunchy members. It's the group with the big park day (on Thursdays) location varies and a "nothing's really off topic" email list.
Chapel Hill Homeschoolers (membership not limited by geography) has upwards of 200 member families and more organized activities. It sponsors enrichment classes on Fridays at a church on the border of CH and Durham.
NCGifts is a groups for families with kids who are special needs and are hsing.
Homeschoolers of Color is for families that have kids who are of color and are hsing.
Christian Homeschoolers of Greater Durham (CHEAGD) is a conservative Christian group with a statement of faith.
Deerstream is a Christian-world view paid coop that meets at a church (I think) 4 days a week.
Dream and Discover....kind of waldorfy, kind of unschool-y coop that meets at an old Montessori school in Durham.
That's off the top of my head....what kind of group are you looking for....I'll post links....