The following data is extracted from Genealogy and Biography of Ontario County, New York.
Justus, son of Ebenezer Williams. was born about 1737 in Deerfield and came to Amherst with his father. in infancy, or was born in what is now (1910) Amherst. He was a soldier in the French and Indian war in Colonel Williams' regiment, from January 24 to November 30, 1757. He was also a soldier in the revolution on the alarm at New Providence, and served in Lieutenant Noah Dickinson's company. In 1783 he was one of the petitioners for the incorporation of the second parish of Amherst. Both he and his son of the same name were voters in 1802, and he or his son was a member of Pacific Lodge of Free Masons, probably the son. In 1790 the first federal census shows that he had in his family at that time three males over sixteen, four under that age and six females. He married Abigail Pomeroy. Of their large family of children we have found but two, though doubtless the others or some of them may be found in the vital records of Amherst. Justus Jr. lived at Amherst and engaged in farming, was town clerk in 1813. 1816 and 1820, married January 1, 1800, Sarah Warner. The other son, Ebenezer, is mentioned elsewhere.
Source: Genealogy and Biography of Ontario County, New York