St. Vrain State Park, State park in Weld County, Colorado, US.

St. Vrain State Park is a recreation area in Colorado's Weld County with 232 acres of water features and 604 acres of green space. Multiple ponds dot the landscape and form the centerpiece, with views of mountains in the distance.

The land was home to Ute, Arapaho and Cheyenne peoples, then passed from Spain to France and to the United States in 1803 with the Louisiana Purchase. Settlers Milo Smith, Perry L. Smith and Elisha Duncan took up land east of St. Vrain and Boulder creeks, and in July 1864 the community built Fort Junction, a sod fort with walls two feet thick, used as a post office from 1866 to 1867. The park was formerly called Barbour Ponds.

The park's name comes from St. Vrain Creek, which honours Céran de Medill St. Vrain, a French trader active in the region in the 1800s. The park was long known as Barbour Ponds before taking the creek's name. Visitors today come for year-round fishing and hiking, and birders watch for the blue heron rookery, the largest in Colorado.

The park is easy to navigate with marked pathways, and you can enjoy multiple activities without lengthy hikes if that is not your preference. Arriving early, especially on weekends, helps you find the best spots along the water before they fill up.

The park was renamed St. Vrain State Park from its earlier name, Barbour Ponds. It holds Colorado's largest rookery of great blue herons, and the reservoir at its centre is called Blue Heron Reservoir, so the birds are the reason for the water's name.