• Jacob Harsen was born in February 1738. He was the son of Albany residents Bernardus and Catharina Pruyn Harsen.
In 1759, he was named constable in the second ward. The next year, he served as firemaster. As a young man, he was identified as a gunsmith who kept a home and shop at Niagara where he was a client of Sir William Johnson. He was known on the frontier as a smith and trader whose principal clients were Indians.
In June 1764, he married Albany native Alida Grosbeck at the Albany Dutch church. Two years later, he took charge of a pew in the church that formerly had belonged to his father. The marriage produced at least seven children. But only the first born was baptized in Albany.
In 1767, he was listed on the Albany assessment roll under his mother's second ward home. Sometime afterward, he moved his large family to the far West where he became a silversmith and one of the pioneer settlers of what became Michigan. By 1778, he had settled on an island in the St. Clair River in Michigan. At different times, he also lived in Detroit.
Jacob Harsen died on Harsen's Island in the spring of 1802. He was one of a number of early Albany tradesmen who settled near Lake Michigan before the American Revolution. His children became prominent residents of the region.4219

• On October 9, 1789, Jacob Hansen gave a plot of land on present day Harsen’s Island to his granddaughter Mary whose parents were Gerrit Greverat and Sara Harden. Greverat and Harden are said to have come from Albany, New York and these two families may be identified with the following genealogical information.4216

• At the close of the last war with England, many new settlers came to the St. Clair country. About this time, Jacob Harsen, a gunsmith, associated with a Mr. Graverset, a silversmith, came to Harsen’s Island.283, p 253