Although there were significant military engagements in Texas during the Civil War, the state was spared destruction on the scale that some other Confederate states experienced. This was partly because of Texas's unique geographical situation.
Texas was a large state, and Union strategists knew that it would be difficult to try to occupy the whole region. It was also on the periphery of the Confederacy, far from the more populated and economically significant states further east. Rather than commit large numbers of Union troops to try to nullify Texas outright, it was decided to simply cut Texas off from the rest of the rebellious states as part of the Anaconda Plan. This would prevent food and other provisions from Texas from supplying the bulk of Confederate forces elsewhere. To accomplish this, Union forces concentrated on securing the Mississippi River, which would severe Texas' supply routes to the east. After the Union victory at the Battle of Vicksburg on July 4, 1863, the Confederacy was split in two and Texas's threat to the Union was largely reduced.
Although some of the last Confederate holdouts were in Texas, towards the war's end, the political will of Texans to fight on had largely deteriorated. By the spring of 1865, news of significant Confederate defeats in the east convinced many Texan secessionists that their cause was lost and that it would be better to surrender to avoid further destruction. Some Texan leaders hoped that their ending of hostilities would work in their favor during the post-war period.
As a result, General John Magruder chose to disband his army before the Union army arrived in force. Confederate soldiers under the command of General Kirby Smith also deserted in large numbers. This likely prevented drawing the conflict out further and prevented further destruction in Texas.