William O'Brien State Park

William O'Brien State Park is a Minnesota state park about 2 miles from the town of Marine on St. Croix. The park is managed by Minnesota's state park and recreation system, and its trail network sits close at hand, with several named trails within about a mile of the park's center. For comfortable weather, late spring through early fall is the easiest window: typical July highs run about 83°F with lows near 60°F, while September averages a milder 74°F high and 50°F low, according to normals from a weather station about 10 miles away near Forest Lake. Winters are cold, with typical January highs around 24°F and lows near 3°F. Cross-country ski trails make up much of what's nearby. Wedge Hill Savanna Trail and Beaver Lodge Trail are each about 0.4 miles away, with Wetland Trail and Prairie Overlook Trail within a mile. Climbers can find Stillwater Ice about 9.7 miles away.