For experienced trail runners who are accustomed to running moderately challenging trails, the Cross Timbers Trail Runs races are likely to be a perfect fit if you’re looking for a race with plenty of steep uphills and downhills as well as terrain that will test your skills and endurance. This race event – which includes a full marathon, half marathon, five-mile and a 50-mile run – takes participants along what has been nicknamed the ‘toughest little trail in Texas,’ the 14-mile Cross Timbers Trail, which lies along the southern shore of Lake Texoma on the state line between Texas and Oklahoma.