The President of The United States of America in an effort to secure safe Washington, D.C. called upon 75,000 State militiamen to serve in the National Armies, this as a result of the fall of Fort Sumter. The U.S. (Union Sates) now at war with the Confederate States. Lincoln's call to arms met with great patriotic  eager men rushed to join military companies in  the North and quickly embarked to guard Washington, D.C. Some troop movements were by steamer boats. The Governor of  Massachusetts spoke to the military companies before they departed saying,
"You have come from the shores of the sounding sea, where lie the ashes of the Pilgrims, and you are bound on a high and noble pilgrimage for Liberty, and the Union and Constitution of your country." The Massachusetts Sixth Infantry went by rail train.

Not many steam boats were available at the time and only so many troops, equipment, and gear could go on these boats so others had to go by rail train. The rail train stopped in Baltimore, Maryland from the North at  President Street Station, which meant to get to Washington, D.C. the troops would have to catch other transportation  or horse drawn trolleys in Baltimore in order to change over to the other rail train to Washington which was at Camden Station.  In Baltimore there were many Southern sympathizers. Outraged that the North would come into Baltimore and stand on Maryland soil the Southern sympathizers  blockaded the trolley routes.

The Massachusetts Sixth Regimental Infantry let off the rail trains only to be confronted by the Southerners whom proceeded to harass them. They yelled "Hurrah for Jeff  Davis" and as a fellow Southerner marched up waving a large Confederate flag at the Massachusetts Sixth Regiment the crowds became thunderous in voice with cheers. The mob followed the Massachusetts Sixth badgering them and taunting them.
All at once the crowd began to throw stones and bricks at the Massachusetts Sixth.  The Massachusetts Sixth then out of panic drew there weapons upon the crowd and fired a volley into them. At the days end four soldiers and twelve civilians lay dead with numerous others wounded. After this Baltimore's mayor and police chief authorized the destruction of key rail bridges to  prevent Union troops from entering the city.

On May 13, Federal troops, including members of the Massachusetts Sixth Regiment attacked in the previous month's  riot, occupied the city and martial law was declared, squelching most subsequent pro Confederate activities. The  police chief, several commissioners, and a number of citizens were arrested for their alleged participation in the riot,  and suspected secessionists, including Francis Scott Key's grandson and a number of state legislators, were held  without charges. Federal forces continued to maintain an occupying presence in Baltimore for the remainder of the war.

Maryland was kept in the Union, but Virginia was lost to the Confederate States along with General Robert E. Lee and Winfield Scott.
North Carolina and Tennessee soon followed Virginia into the Confederacy. The cry from the North was now "On To Richmond!"
The rebel capital was moved from Montgomery, Alabama to Richmond, Virginia. General Beauregard was now stationed at Manassas Junction after regaining Fort Sumter. Southern troops were also at Fairfax Court within sight of the Federal capital.
 

Baltimore Riots Time Line -

     April 19, 1861 - 6th Massachusetts Regiment passing through the city comes under attack by civilian Southern Sympathizers.
     April 21, 1861 - rioting continues in Baltimore rails and trains damaged cutting off Washington's rail trains to the North.
     April 23, 1861 - riots continue unabated. General B.F. Butler moving towards Washington with the Massachusetts volunteers
                                   offers the services of  his troops to help restore order but is needed in Washington.
     April 28, 1861 - turmoil in Baltimore and the threat of secession  in the rest of Maryland threatens the Federal capital's
                                   communications.
     May  12, 1861 - General Benjamin Butler moves his troops into Baltimore without authorization.
     May  15, 1861 - General Butler continues his occupancy in Baltimore. Washington sees that this action is a good safeguard.
 

Federal Army finally strikes at Confederacy