Northern United States

Before the 19th century westward expansion, the "Northern United States" corresponded to the present day New England region.

Northern states had all passed some form of legislation to abolish slavery by 1804.

There is, however, some historical disagreement as to exactly which states comprised the North in the context of the Civil War as five slave-holding states largely remained with the Union: the southern border states of Missouri, Kentucky, West Virginia, Maryland, and Delaware, along with the disputed Indian Territory, though Missouri and Kentucky had dual competing Confederate and Unionist governments with the Confederate government of Kentucky and the Confederate government of Missouri and the Confederacy controlled more than half of Kentucky and the southern portion of Missouri early in the war.

[7] The U.S. Census Bureau also includes the northernmost states of the Northwest, that are within the West Region.

Most of the Northern states have warm to hot summers and significant snowfall during the winter.

Map of the division of the states during the American Civil War (1861–1865); states in blue represent northern Union states, those in light blue representing five largely Union-supporting border southern states that permitted slavery, known as border states , and both Missouri and Kentucky , which had competing Confederate and Unionist governments, and states in red representing southern seceded states, known as the Confederate States of America prior to the end of the American Civil War