In Washington, DC, the District of Columbia militia called out and sworn in for three months
The War Department gave orders just after midnight for the calling out of the entire militia of the District of Columbia. During the following morning and afternoon the militia companies gathered and were marched to the War Department to be administered the oath of allegiance to the United States and enlist for three months of service. A thousand men enrolled but a significant number refused the oath and were disarmed and stricken from the rolls of their units. (By John Osborne)
J. Blakeslee Frost, ed., The Rebellion of the United States or the War of 1861 ... (Boston, MA: author, 1862), 120-121.