By: The Essex Institute, Pub. 1916, reprinted 2025, 542, Index soft cover, ISBN #978-1-63914-649-9. By: The Essex Institute, Pub. 1920, reprinted 2025, 502, Index soft cover, ISBN #978-1-63914-651-2. Essex County was created in 1643 and lies in the Northeastern corner of the state bordering the Atlantic Ocean and New Hampshire. Probate records are wonderful source for genealogical research due to wide variety of family members being named within along with a inventory of the deceased estate. There are approximately 390 Probated Wills with approximately 3,600 individuals being mentioned in the Index.