1864 National Union National Convention

The 1864 National Union National Convention was the United States presidential nominating convention of the National Union Party, which met in Baltimore, Maryland on June 7 and 8, 1864. National Union was the name adopted by the main faction of the Republican Party in a coalition with many, if not most, War Democrats and Unconditional Unionists after some Republicans and War Democrats nominated John C. Frémont over Lincoln a few weeks earlier.

Source: Wikipedia — 1864 National Union National Convention (CC BY-SA 4.0)