The last named organization owes its birth to the doubts and complications of the darkest hour of the War of Secession.

Unite to stand behind the President with our full strength, was the slogan of the men who met in January, 1863, to form the plans for the new association.

At the beginning there was talk of adopting the name "Loyal League." The first work of the club was the organization of negro troops in New York City.

Despite the opposition of Governor Seymour, and the ridicule of the newspapers, who held up the idea of the negro as a soldier as a huge joke, the Leaguers persisted in their efforts, with the result that in December, 1863, the Twentieth Regiment of U.S.coloured troops was enlisted, and within a few months, two more regiments, known as the Twenty-sixth and the Thirty-first.
In those days the club-house faced Union Square, at the junction of Seventeenth Street and Broadway.

Early in 1868 the Union League moved to a house at the corner of Madison Avenue and Twenty-sixth Street, the building afterwards to be occupied in turn by the University Club and the Manhattan Club.