In the southeast part of Austin, not far from the airport (consider this when you have a long layover), this wooded preserve lies at the confluence of two streams, with waterfalls flowing over limestone ledges. It offers a 2.8-mile hike-and-bike trail, as well as fishing, swimming, and camping; there’s even a small historic site. This is a popular spot on fine-weather weekends and sometimes gets closed when it reaches capacity—call ahead or check the park’s Twitter feed or Facebook posts (links are on the website).