In 1814, Woodbridge's old friend
Lewis Cass, who had become Governor of the
Michigan Territory, encouraged him to accept appointments as Secretary of the Territory and as the collector of customs at the Port of Detroit. On October 15, 1814, Woodbridge reluctantly accepted the appointments from President
James Madison and moved to
Detroit, Michigan. During the frequent absences of Cass, Woodbridge served as acting governor. In 1817, Woodbridge became a trustee of the
University of Michigan. Under the rules of territorial government, the territory did not have representation in the U.S. Congress. Woodbridge influenced Congress to pass legislation authorizing the selection of a non-voting delegate to Congress. Woodbridge became the Michigan Territory's first delegate, serving in the
16th Congress from March 4, 1819, to his resignation on August 9, 1820, due to illness in his family.
Solomon Sibley succeeded Woodbridge as delegate. He remained the Territorial Secretary while delegate. As a delegate, Woodbridge worked for the passage of legislation that recognized old French land titles in the territory according to the terms of the previously signed treaties. He also secured approval for the construction of government roads from the
Great Miami River to Detroit, and from Detroit to Chicago. He was also a strong advocate for Michigan's claim to the
Toledo Strip, which was disputed with the state of Ohio. In 1828, he was appointed one of three Territorial Supreme Court justice by President
John Quincy Adams, succeeding
James Witherell and serving in this capacity until 1832 when his term expired and President
Andrew Jackson chose a replacement who was not from the
Whig Party as Woodbridge was. ==Politics and Governorship in the State of Michigan==