The William Beebe papers are comprised of Beebe's hand-written genealogical research notes, forty history and genealogical reference books, and some personal papers.

The genealogical research is organized around 250 family names. Sources cited are town, state, and church records, family genealogies, memoirs, local histories, newspaper genealogy inquiry services, and correspondence. Some land and probate record references are included along with hand-drawn maps and historical notes on Lyme roads and properties as they relate to particular families. Data are drawn from Old Saybrook, Salem, Colchester, Montville, Waterford, New London and New Britain sources as well as from Lyme and Old Lyme.

Beebe's personal papers include some family photographs, Wesleyan College and fraternity materials, printed matter from Lyme organizations and some personal correspondence. Material relating to his service to the Town of Lyme and the Connecticut General Assembly, as organist for the First Congregational Church or as a jazz musician are minimal. His obituary and other tributes in town publications provide additional sources on these topics.