Texas Local Government Code - LOC GOV'T § 321.001. Eligible Counties

(a) A county that borders on the Gulf of Mexico and that has within its boundaries one or more islands or parts of islands suitable for park purposes may act under this chapter for the purpose of improving, equipping, maintaining, financing, and operating one or more parks on those islands.

(b) The suitability of an island or part of an island for park purposes is conclusively established when the commissioners court of the county by order makes a finding that the island or part of an island is suitable for park purposes.