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

Berret was born in Carroll County, Maryland in 1815. In 1836, at the age of 21, he was elected to the Maryland state legislature, where he served two one-year terms from 1837 to 1839. Upon leaving the legislature he was appointed to an office in the U.S. Treasury by President Martin Van Buren He served in the Treasury until 1853, when he Franklin Pierce appointed him Postmaster of the District of Columbia.^[1] He served on the inaugural committee for Presidents James Buchanan and Abraham Lincoln.

In 1858, Berret was nominated as the mayoral candidate for the Anti-Know-Nothing Party, a coalition of political parties that had been formed in 1854 as an opposition to the Know-Nothings' electoral successes in the city. 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. Thus Berret was pitted against Richard Wallach, the U.S. Marshal for the District; both men were of equal popularity, means, and political reputation, but on Election Day Berret won by 680 votes.

The election sparked a fierce rivalry between Wallach and Berret, enough so that when Berret defeated Wallach again in the 1860 contest by only 24 votes, Wallach published editorials in every Washington newspaper charging Bettet with massive fraud in both elections. ^[2]

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, jailed in the Old Capitol Prison, then sent to Fort Lafayette, New York. Three weeks later, when no evidence of collaboration with the enemy had surfaced, Seward had Berret released and returned to Washington — on the condition that he immediately resign as mayor. Berret telegraphed his resignation to the Washington City Councils, who had already elected Wallach to replace him.^[3]

Berret eventually became friends with Lincoln, although he declined when the President offered to appoint him commissioner of the emancipation of slaves in the District of Columbia. In 1872, however, Ulysses S. Grant nominated him to the board of police commissioners^[4], which he accepted. He would later serve on another Presidential inaugural committee, this time for Grover Cleveland. Berret died in 1901