Why did New Hampshire claim Vermont?

New Hampshire claimed Vermont primarily due to overlapping land grants issued by colonial authorities, which created confusion over territorial boundaries. After the American Revolution, New Hampshire continued to assert its claim to Vermont, viewing it as part of its territory. However, Vermont declared its independence in 1777 and operated as a separate republic until it became the 14th state in 1791, ultimately resolving the dispute. The conflict was rooted in colonial land policies and competing interests of settlers in the region.