The land at Louise F. Cosca Regional Park preserves a long history that begins when Southern Maryland lay beneath the warm shallow Miocene Sea twenty to ten million years ago, leaving fossils of sharks teeth, mollusks, crocodiles, whales, and turtles, and continues through the Ice Ages, when glacial advances lowered sea levels and later melting waters cut deep river channels and flooded the ancient Susquehanna River Valley to form the Chesapeake Bay. Archaeological evidence shows that American Indians visited and inhabited Prince George's County for the last 10,000 years, first as hunters and gatherers who used nearby springs, streambed stone, wetlands, and other natural resources, and later in larger farming villages; by 1608, when Captain John Smith explored the Chesapeake Bay and its tributaries, Algonquian-speaking Piscataway-Conoy people were the principal tribe in Southern Maryland, with their main village on Piscataway Creek west of here, and many descendants still live in Prince George's County today. By the late 1600s, European colonists had settled in Maryland and established tobacco plantations dependent upon enslaved Africans, and this park formed part of the tracts called Brother's Delight, established by John Wheeler in 1673, and Sister's Delight, established by Hillary Ball in 1703, with later ownership by John Simpson and Edward Lanham; in 1860 Emily Edelin owned at least 19 enslaved African Americans, and after slavery was abolished in 1865 large plantations failed and were divided into smaller farms. Remains of that past survive in the park, including the Thrift Schoolhouse, built in 1884 to replace an earlier school established in 1868, old wagon trails, a former apple orchard trail, and the remains of a whiskey still. In 1962 the Maryland-National Capital Park and Planning Commission purchased 500 acres from the heirs of Rebecca Berger to develop Clinton Regional Park, later renamed for Louise F. Cosca, and in 1970 Clearwater Nature Center, the first in Prince George's County, was dedicated there as conservation became increasingly important.