In which year did West Virginia join the United States?

West Virginia joined the United States on June 20, 1863. This event was significant as it occurred during the American Civil War, a time when Virginia was divided over the issue of secession. The northwestern region of Virginia, which would become West Virginia, opposed secession from the Union and thus sought to establish itself as a separate state. After several agreements and a referendum, Congress admitted West Virginia as the 35th state. This historical context is crucial in understanding the complexities surrounding its statehood during a tumultuous period in American history. The other years listed do not align with the establishment of West Virginia as a separate state: 1776 marked the signing of the Declaration of Independence, 1789 was the year the U.S. Constitution took effect, and 1810 falls outside the timeframe relevant to West Virginia's admission into the Union.