- The Sedgwick Collection at New Haven Colony Historical Society
- Full catalog of this immense collection, plus a history of Sedgwick Genealological Research.
- The Massachusetts Historical Society Library
- A very large Sedgwick Family collection
relating largely to Theodore Sedgwick (1746 - 1813) and his descendants.
Search for Sedgwick at their "Abigail" search engine
- Calvert County (Maryland) Historical Society
- Family Collections for (Thomas) Sedwick and several related families.
- Buy and read History of Calvert County Maryland by Charles Stein immediately!
- The State Historical Society of Wisconsin
- Not a specific Sedgwick collection, but they have a lot of Sedgwick materials
- Go to the Library or Archives sections and search