Final answer:
West Virginia was formed due to anti-secession sentiment and opposition to slavery in the western region of Virginia, thus seceding from Virginia and becoming a state in January 1863.
Step-by-step explanation:
Formation of West Virginia
West Virginia was formed due to differing opinions on secession and slavery during the Civil War period. The majority of voters in the mountainous areas of the Upper South, including western Virginia, opposed secession, in contrast to the rest of Virginia.
The residents of this region were reluctant to fight for slavery, which played a significant role in their decision-making. Invoking the idea that if a state could secede from the nation then a county could secede from a state, they voted for an "ordinance of dismemberment." As a result, West Virginia became an official state in January 1863, during the American Civil War, when the Union admitted the area as it did not recognize Virginia's secession.