April 15, 1861, Virginia's political leaders quickly set in motion the process of seceding from the Union and joining the Confederacy. Even before secession was formally accomplished, Virginia agreed to coordinate its state military forces with the Confederacy and began to seize federal property. The United States Regular Army garrison under the command of Col. Justin Dimick held Fort Monroe, a nearly impregnable fortress at Old Point Comfort on the southern tip of the Virginia Peninsula between the York River and the James River where they empty into Chesapeake Bay. The bay was to the east of the fort and Hampton Roads was to the south. The fort was supported by the Union Navy at Hampton Roads and could be reinforced and resupplied by water without attack by shore batteries or harassment by the nearly non-existent Virginia or Confederate naval forces. The fort was nearly immune from attack from the land side since it could be approached only over a narrow causeway and a narrow isthmus and had massive walls and hundreds of cannons. An inlet called Mill Creek was the body of water that almost cut the fort off from mainland of the Peninsula. Col. Dimick refused to surrender the fort and the small and poorly equipped Virginia (soon to be Confederate) militia forces in the area had no hope of taking the fort by force, especially after April 20, 1861, when the small Union garrison was reinforced by two Massachusetts volunteer regiments within a few days of the Virginia convention voting to secede from the Union on April 17, 1861. This important fort would provide a base for the blockade of Norfolk, Virginia, and the Chesapeake Bay and for the recovery of southeast Virginia and the Virginia Peninsula for the Union. Because Massachusetts militia forces were ready to respond to President Lincoln's call for volunteers, two 90–day regiments, the 3rd Massachusetts Militia commanded by Col. David W. Wardrop and the 4th Massachusetts Militia commanded by Col. Abner B. Packard, were able to reinforce Fort Monroe's garrison of 415 regulars within five days of the President's call. The 4th Massachusetts was the first to arrive. These reinforcements helped assure that this strong point and base of operations would be fully prepared for defense and saved for the Union. On May 13, 1861, the 1st Regiment, Vermont Volunteer Infantry under Col. J. Wolcott Phelps joined the garrison and several other