Gilman returned to the East, and married Hannah Robbins of
Plymouth, Massachusetts, at that place in February 1790, and they moved to Marietta. The couple had nine children born between 1790 and 1808, including
Winthrop Sargent Gilman. Gilman opened a store in
Fort Harmar in 1792, and was clerk of courts for
Washington County from 1795 to 1803. In 1802, Gilman was elected as a
Federalist delegate to the
convention to write a constitution for the new state of
Ohio. He voted at the convention against
slavery and for civil rights and
suffrage of black people. In 1801, Gilman began a shipbuilding business. His ships would sail down the
Ohio River and
Mississippi River, and thence to ports on the
Atlantic Ocean. This business thrived until the
Embargo Act of 1807 destroyed trade. Gilman also had extensive landholdings in Ohio. In 1810, he owned , sixth most in the state. ==Return east==