Middlefield Historical Society is a bit of a hidden gem. Almost everyone who studies the county knows of the Middlesex County Historical Society, which - although based in Middletown - covers the entire county. Few have heard of Middlefield's separate institution. They've missed out.
Based in the Middlefield Community Center, the Society's museum occupies one crowded room. That room is jammed with everything from historic quilts to cemetery indexes. My last visit was to explore the extensive records taken during a survey and subsequent restoration of Middlefield's Old North Burying Ground. The inscription records are priceless. The stones are very worn, and many inscriptions are now unreadable. You'll need a member familiar with the collection to guide you, but I suspect you may find more about your family's past than you ever dreamed possible.
To access the museum, call (860) 349-0665. Be patient. Members are busy, and it may take you awhile to find someone who can let you in.