Feb. 1 – The Secession Convention approves an ordinance withdrawing Texas from Union because "the power of the Federal Government is sought to be made a weapon with which to strike down the interests and prosperity of the people of Texas and her Sister slaveholding States"; the action is ratified by the voters on Feb. 23 in a referendum vote. Secession is official on March 2.
Feb. 13 – Robert E. Lee is ordered to return to Washington from regimental headquarters at Fort Mason to assume command of the Union Army. Instead, Lee resigns his commission; he assumes command of Confederate forces by June 1862.
March 1 – Texas is accepted as a state by the provisional government of the Confederate States of America, even before its secession from the Union is official.
March 5 – The Secession Convention approves an ordinance accepting Confederate statehood.
March 16 – Sam Houston resigns as governor in protest against secession.
March 28 – Battle of Glorieta. Gen. H.H. Sibley's brigade forced to return to Texas, ending the attempt to take New Mexico.
Aug. 10 – About 68 Union loyalists, mostly German immigrants from the area of Comfort, in Central Texas, start for Mexico in an attempt to reach U.S. troops; 19 are killed by Confederates on the Nueces River. Eight others are killed on Oct. 18 at the Rio Grande. Others drown attempting to swim the river. (The loyalists' deaths are commemorated in Comfort by the Treue der Union [True to the Union] monument.)
Aug. 16-18 – U.S. Navy bombards Corpus Christi, attempts to take city are repulsed.
Oct. 8 – Federal forces capture Galveston.
October – Forty-two men thought to be Union sympathizers are hanged at various times during October in Gainesville.
Jan. 1 – Confederate forces retake Galveston.
July 26 – Sam Houston dies in Huntsville from pneumonia at age 70.
Sept. 8 – Battle of Sabine Pass. Federal forces repulsed by unit led by Lt. Dick Dowling.
Nov. 2-6 – Federal forces take Brownsville.
July 30 – Confederate forces reoccupy Brownsville.
May 13 – The Battle of Palmito Ranch is fought near Brownsville, the last land battle of the Civil War. After the Confederate's victory, they learned the Western Rebel states had authorized the disbanding of armies, and accepted a truce with the Union forces a few days later.