Vermont became the first state to join the Union after the original 13 states. Congress admitted Vermont as the 14th state on March 4, 1791, making it an important milestone in the early expansion of the United States.
Before statehood, Vermont existed as an independent republic from 1777 until 1791. Its government issued documents, maintained institutions, and used the name Vermont Republic. A long-running territorial dispute with New York complicated Vermont's path into the Union; an agreement and payment helped resolve the disagreement.
Kentucky is an easy state to confuse with Vermont because Congress authorized Kentucky's admission before Vermont's. Kentucky, however, entered the Union later, on June 1, 1792, as the 15th state. Vermont's admission date therefore gives it priority as the first post-original-13 state.
Vermont's early constitution also prohibited slavery, though the state's legal history and enforcement were more complicated than a single constitutional clause suggests. Its admission changed the Union's political geography and added a new state north of Massachusetts and New York.