Early settlers to Illinois, in an attempt to describe the unfamiliar terrain they were encountering, referred to it as "a sea of grass with pretty flowers." Today Goose Lake Prairie State Natural Area serves as testimony to the prairies that once covered nearly 60% of the state. More than half of Goose Lake Prairie is a dedicated nature preserve, protected by law for future generations from any change to the natural environment. In addition to furnishing a look into Illinois' past, the prairie provides important nesting habitat for endangered or threatened species of birds, such as the upland sandpiper and Henslow's sparrow. Tall prairie grasses, including big bluestem, Indian grass and switch grass, make up 60% of the prairie. By far the tallest of these is prairie cordgrass, commonly reaching heights of 8 to 12 feet. Broad-leaved flowering plants, known collectively as forbs, compose the prairie's other 40%.

• Hike Tall Grass Nature Trail and see the largest stand of tall grass prairie remaining in Illinois.
• Hike Prairie View Trail to the highest point in Goose Lake Prairie - a strip mine spoil mound - with panoramic view of reclaimed mine areas, prairie and prairie marsh.