For state public access, Lake Sebago in Maine has Sebago Lake State Park
http://www.maine.gov/cgi-bin/online/....pl?park_id=26 with 1342-acres, and Lake Winnipesaukee in New Hampshire has Ellacoya State Beach and RV Park
www.nhstateparks.com/ellacoya.html with 65.5-acres.
So, that's Maine with 1342-acres, and New Hampshire with 65.5-acres, for state public access.
If you take a closer look at each facility, Sebago and Ellacoya, you begin to see what's what, with what each state area has for public use on their big lake. Looking at the google earth view, more than half of Ellacoya's 65.5 acres seem to be on the south side of Rt 11, and is entirely wooded, totally undeveloped acreage which includes the Poor Farm brook.