Texas Local Government Code - LOC GOV'T § 331.008. Municipal and County Cooperation

(a) A municipality and a county may act in cooperation with each other in the exercise of authority under this chapter. A park, playground, museum, or site acquired jointly by a municipality and county acting in cooperation is under joint management and control.

(b) If a municipality owns land outside its limits that is devoted to use as a playground or park and is adjacent to land that is owned by the county in which the municipality is situated and that is devoted to use as a public park, the municipality or county may purchase the adjacent land from the other on terms agreed to by each. The purchased land must be used in connection with the adjacent lands and devoted to use as a playground or park. The consideration for the purchase must be sufficient to provide for the payment of any outstanding bonded indebtedness incurred by the seller in acquiring the land. All sums credited to the sinking fund for the indebtedness shall be subtracted from the face value of the unpaid bonds in determining the outstanding indebtedness.

(c) A municipality and the county in which the municipality is located that separately own adjacent land that is outside the municipal limits and is dedicated to use as a park or playground may by lease or other arrangement provide for the single management and control of the land. The agreement may be for any period and on any terms agreed to by the municipality and county. The agreement must vest exclusive management and control of the entirety of the lands for the benefit of the public as a recreational park or playground in the governing body of the municipality or the commissioners court of the county. Such an agreement does not affect the power of either the municipality or the county to contribute funds to the maintenance and improvement of the park or playground or the facilities of the park or playground.