Final answer:
The 'Peace Democrats' in the North who opposed the Civil War were known as the Copperheads, a group prominent in the Midwest and among northern immigrant Catholics, led by figures like Clement Vallandingham and active in the peace movement during the Election of 1864.
Step-by-step explanation:
Also known as 'Peace Democrats', the faction of the Democratic Party in the North that was known for their opposition to the Civil War were the Copperheads. They were a diverse socioeconomic group mainly from the southern Midwest and the immigrant Catholics of northern cities. One of the key figures of the Copperhead movement was Ohio Representative Clement Vallandingham. The Copperheads opposed Abraham Lincoln's emancipation policies and favored a vision of the United States as 'the white man's home.' They gained particular prominence in the peace movement close to the Election of 1864, advocating for an immediate end to the war and the ousting of Lincoln from office.