Texas was the second largest state in the U.S, both in area size and in population, while also sharing a border with several Mexican states to the south-west. Its capital is Austin, while its largest city is Houston. It was the only U.S. state to be an independent state before joining the U.S. Outside the major cities, the state is very hot, rural and sparsely populated. It's mostly desert and dry in the west and north. With more humid cost lines and swamps in the east and mountains in the south.
Not a lot is known about Texas during the outbreak. It can be assumed that it followed the example of California, with state and local police being among the first responders, with these first responders being joined by military units when a state of emergency was declared, and in accordance with the Federal Government's plans.
The city of Houston appears briefly in flashback, with Abraham Ford surviving with his family in a grocery store.
The city of Austin is shown to be bombed in "I Lose People..." meaning it fell victim to Operation Cobalt.
A couple of years into the outbreak, the Lonestar Power & Light power plant suffers a meltdown, leaving the area around it radioactive and creating radioactive walkers. A year later, the plant undergoes a second meltdown which will kill anyone left in the area.