On May 31, 1861, The Confederacy gave General P. G. T. Beauregard command of the "Alexandria Line," which includes all of northern Virginia. He would be charged with defending the territory against invasion. He would soon be fending off General Irwin McDowell's army at Manassas.
Out west, in Missouri, General Nathaniel Lyon was given command of all the Union troops in the state, replacing General William Harney.
Even further west, the Union evacuated some of the forts in the Indian Territory. Most of those troops arrived in Leavenworth, Kansas, on this date. The path they took would later be known as the Chisholm Trail, named after one of their guides, Jesse Chisholm. After the war western ranchers would use the trail to get their cattle to the eastern markets.