The park may be only 13 miles from the Texas state capitol, but it feels like a world away. The main draws are the two waterfalls, both the result of Onion Creek flowing over limestone ledges. Cool off with a swim in the swimming holes below or fish from the shores. In between the falls, large boulders are perfect for bouldering. Elsewhere at McKinney, nearly nine miles of hiking trails and biking trails wind their way through Hill Country woods, past an ancient rock shelter and Old Baldy, one of the oldest cypress trees in Texas. Many visit just for the day, but with five loops housing 81 camping spots (with all electricity, water hookups, a picnic table, and fire ring), it’s easy to stay overnight.

• Best for those who need more power: All nine sites at the Little Oak Camping Area offer 50 amps.
• Best to escape the crowds: The Moss Loop Camping Area, at the southern edge of the campground, has just five campsites.
• Best for comfort: Six cabins offer bunk beds for four, with air conditioning, a mini fridge, and microwave, though no bathroom or linens.

1. During peak season, plan to reserve a site as soon as you know your dates. Campsites and cabins can be reserved up to five months in advance. 
2. If you don’t have a reservation, arrive at the park first thing in the morning to try for an unreserved site.
3. If your plans are flexible, try to visit during the week, during non-holiday periods, or over winter.

Peak season runs from March through November. Temperatures soar in summer, making it an ideal time to cool off with a dip in the river and pools. To see the waterfalls at their fullest, visit during the wet season of May through September, as the river can be really low otherwise. On holidays and special event weekends, a three-night minimum stay is required for the cabins, instead of the regular two-night weekend minimum.

• Onion Creek is prone to flooding after rainfall.
• Water shoes are a good idea; some trails require a creek crossing.
• Food, alcohol, glass, coolers, speakers, Frisbees, and balls are prohibited in the Upper Falls and Lower Falls areas.
• Fishing licenses are not required to fish from shore inside the park.
• Pets are not allowed in the water, inside buildings, or around the cabins.
• Bring or purchase firewood from vending near camping loops. Gathering firewood is prohibited in the park.