Gambrill State Park is a beautiful mountain park located on the ridge of the Catoctin Mountains and its most popular feature is the network of trails. The Yellow Trail is a challenging and demanding ride. The trail is rocky singletrack running through dense woods and over mountainous terrain. There are some strenuous climbs involved as well. You will reach the top of High Knob where there are three stone overlooks with breathtaking views of the Frederick and Middletown Valleys.