Tex. Local Government Code § 374.902

(a) Unless the context clearly requires otherwise, a statement in this chapter that applies to a mayor applies to the county judge of a county exercising powers under this section, a statement that applies to the governing body of a municipality applies to the county's commissioners court, and a statement that applies to a municipality applies to the county.

(b) A county with a population of more than 250,000 and located along an international border or a county with a population of more than 1.3 million may exercise the powers provided for municipalities under this chapter with respect to areas of the county that are not within the corporate boundaries of a municipality. A county with a population of more than 250,000 and located along an international border may exercise the powers provided for municipalities under this chapter with respect to areas of the county located within the corporate boundaries of a municipality, if the municipality approves the county's participation in an urban renewal project through an interlocal agreement under Chapter 791, Government Code. The county may not exercise those powers until the commissioners court of the county adopts a resolution in the manner provided by Section 374.011 for adoption of a resolution by a municipality. The resolution must be approved at an election held in the county in the manner provided for a municipal election under Section 374.011. The adoption of the resolution is not approved unless a majority of the voters who vote on the question in the entire county as well as in each municipality in the county approve the adoption of the resolution. In a municipality that is only partially located in the affected county, only voters who reside in the county may vote.