The northern states of America are Connecticut, Illinois, Indiana, Iowa, Kansas, Maine, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Hampshire, New Jersey, New York, North Dakota, Ohio, Pennsylvania, Rhode Island, South Dakota, Vermont and Wisconsin. These states are historically identified as the Union states during the American Civil War.
Although the northern states are now considered one region, they were historically divided into four distinct areas: New England, the Middle Atlantic states, the Old Northwest (East North Central States) and the Great Plains (West North Central States). The earliest official recognition of the northern states as a regional entity was in 1796, when George Washington used the terms "North" (Union states) and "South" (Confederate states) in referring to the opposing policies and sentiments on slavery between the two regions. Besides sharing a common ideology, the northern states were also bound by political, educational, cultural and economic ties as increasing immigration and trade served to homogenize individual state interests.
The northern states are largely independent in the 21st century, but they share similar qualities, such as strong manufacturing sectors and high population densities relative to the rest of the country. Due to America's federal system and greater autonomy between states, the term "northern states" is not widely used. It is more common to separate the states into smaller regions, such as New England and the Midwest.