164 structures built by the Civilian Conservation Corps and the Works Progress Administration survive, the largest collection of New Deal projects in Minnesota.

[8] The St. Croix River's exposure of a characteristic yellow clay deposit gave the historic Yellowbanks section of the park its name.

However the underlying basalt and sandstone is exposed in one area along the Kettle River known as the Highbanks, where a final ancient flood of meltwater scoured away the sediments.

[8] In addition to the two rivers, at least ten other streams flow through the park, creating a watershed of hundreds of square miles.

[9] The present secondary forest is a mix of pines, black spruce, sugar maple, and basswood.

Large mammals found in the park include white-tailed deer, coyotes, raccoons, gray and red foxes, beavers, bobcats, black bears, and timber wolves.

[11] Evidence of Native American occupation in the park and the St. Croix River Valley has been found dating back 5,000 years.

From 1894 to 1898 the Empire Lumber Company operated a rail line, the Flemming Railroad, to transport logs cut farther inland to the St. Croix River.

The line ended at Yellowbanks where the logs were rolled down the steep bluffs and floated to sawmills downriver.

[5] Pine County had the most tax delinquent property in Minnesota and suffered abject environmental degradation from cultivation and wildfires like the Great Hinckley Fire.

[7] The other three were group centers constructed by WPA crews: Norway Point for boys, St. John's Landing for girls, and Head of the Rapids for handicapped children.

[7] Some crews planted pine, spruce, and hardwood trees to begin reforestation while others conducted wildlife and fire protection work.

[12] As additional properties were added, St. Croix Recreational Demonstration Area grew to 30,000 acres (120 km2), only slightly smaller than the country's largest RDA at Custer State Park in South Dakota.

Visitors can climb the 134 steps to the cab of the fire tower; interpretive signs describe the layers of the forest habitat and features of the surrounding countryside.