Thursday December 20 1860

• The following are the Four General Officers in the Union Regular Army at the outbreak of the Civil War:
  • Brevet Lieutenant General Winfield Scott. U.S.A.
  • Brevet Major General David E. Twiggs, U.S.A.
  • Brevet Major General John Ellis Wool, U.S.A.
  • Brigadier General William Selby Harney, USA
• The ordinance of secession is adopted by the South Carolina Convention, by the unanimous vote of 169 to 0 in the Institute Hall, Charleston, SC.

Friday December 20 1861

• William High Keim, USA, is appointed Brig. Gen.
• John McCauley Palmer, USA, is appointed Brig. Gen.
• Two warships of the British Royal Navy convoy troops to Canada in case a satisfactory solution to the "Trent" affair is not achieved.
• A stone fleet, consisting of old whaling vessels, are sunk by the Federal Navy in an attempt to prevent Confederate blockade runners from entering Charleston Harbor, SC.
• Engagement at Dranesville, VA, between Brig. Gen. George A. McCall, USA, and Brig. Gen. JEB Stuart, CSA, Cavalry.

Saturday December 20 1862

• Skirmish at Cane Hill, AR.
• Skirmish at Cold Water, MS.
• Operations against Vicksburg, MS. (Dec 20-Jan 3)
• The Federal Expedition under the command of Maj. Gen. William Tecumseh Sherman, USA, embarks at Memphis, TN, for Vicksburg, MS.
• Federal operations against the Maj. Gen. Earl Van Dorn Confederate raid, MS. (Dec 20-28)
• The Confederate capture of Holly Springs, MS, by Maj. Gen. Earl Van Dorn's CSA, troops moving from Grenada, MS, and capturing 1,500 of Maj. Gen. Ulysses S. Grant's men and over $1,500,000 of military supplies. Grant is now forced to withdraw to LaGrange, TN, and forgo his advance on Vicksburg, MS.
• Brig. Gen. Samuel P. Carter's, USA, Raid into East Tennessee and Southwest Virginia. (Dec 20-Jan 5)
• The Confederate capture of Humboldt,TN, by Maj. Gen. Nathan Bedford Forrest, CSA.
• Skirmish at Railroad Crossing, Forked Deer River, TN, with Maj. Gen. Nathan Bedford Forrest, CSA.
• The Confederate capture of Trenton, TN, by Maj. Gen. Nathan Bedford Forrest, CSA.
• Skirmishes at Kelly's Ford, VA. (Dec 20-22)
• Skirmish near Occoquan, VA.
• Skirmish near Halltown, WV.
• Secretary of the Treasury, Salmon P. Chase also tenders his resignation, which President Lincoln refuses to accept.

Sunday December 20 1863

• Federal scout from Lexington, MO.

Tuesday December 20 1864

• John McArthur, U.S.A., is appointed Maj. Gen.
• The Confederate evacuation of Savannah, GA, by Lieut. Gen. William Hardee, CSA.
• Federal expeditions from Cape Girardeau and Dallas, MO, to Cherokee Bay, AR, and the Saint Francis River, with skirmishes, with guerrillas. (Dec 20-Jan 4)
• The USS Hartford, and its commander, Admiral David G. Farragut, arrives in New York City Harbor for repairs.
• Engagement at Poplar Point, NC. (Dec 20-22)
• Skirmish near the Pocotaligo Road, SC, as the 33rd US Colored Infantry drives off the 300+ plus Rebels contesting their advance near the Tullifmny Creek, capturing men and supplies.
• Skirmish at Columbia, TN.
• The capture and the destruction of the salt-works at Saltville, VA, by Maj. Gen. George Stoneman, USA. (Dec 20-21)

Wednesday December 20 1865