Why was the border state of Marylnd vital to the Union?

Maryland was vital to the Union during the Civil War for several reasons. Its strategic location bordered the Confederate capital of Richmond, Virginia, and was crucial for protecting Washington, D.C., from potential attack. Additionally, Maryland's transportation routes, including railroads and waterways, facilitated troop movements and supply lines. The state's population was also divided in loyalty, making its allegiance significant for maintaining support in the border states.