Where do I file for custody?
Generally, you would file for custody in the “home state” of the child. The "home state" is the state where your child has lived with a parent or a person acting as a parent for at least the past six months. If your child is less than six months old, then your child's home state is the state where s/he has lived since birth. Leaving the state for a short period of time does not change your child's home state.*
If you and your child recently moved to a new state, generally you cannot file for custody in that new state until you have lived there for at least six months. Until then, you or the other parent can start a custody action in the state you just left (where your child most recently lived for at least six months) if one of the child’s parents continues to live in that state.**
* Tex. Fam. Code § 152.102
** Tex. Fam. Code § 152.201