James Gabriel Berret (February 12, 1815 – April 14, 1901) was an American politician who served as a Maryland state legislator from 1837 to 1839 and again in 1891 and as the eighteenth Mayor of Washington, District of Columbia, from 1858 to 1861, when he was forced to resign from office after being jailed by the Lincoln administration for sedition.

In 1836, at the age of 21, he was elected to the Maryland state legislature to represent the newly formed Carroll County.

[3] Upon leaving the legislature he was appointed to an office in the U.S. Treasury by President Martin Van Buren and moved to Washington, DC.

However, by 1858, the Know-Nothings were a spent force, and the U.S. political landscape was such that the Republicans, who had once been a part of the Anti-Know-Nothing coalition, now stood independently from it as an opposition to President Buchanan and the Supreme Court's decision in Dred Scott v. Sandford.

[1] With the outbreak of the Civil War in 1861, the Republicans in the U.S. Congress pushed through legislation that required all public officers in Union territory to take oaths of allegiance to the United States.

When Berret refused, insisting that his oath as mayor of the nation's capital should suffice, Secretary of State William H. Seward had him arrested,[5] jailed in the Old Capitol Prison, then sent to Fort Lafayette, New York.

[6] Three weeks later, when no evidence of collaboration with the enemy surfaced, Seward had Berret released and returned to Washington—on the condition that he immediately resign as mayor.