Pine Lick Trail is connected to landmarks of national historic significance. The Mason-Dixon Line marks the border between Maryland and Pennsylvania as well as the northern edge of Green Ridge State Forest. Completed in the 1760s, this 230-mile east-west line was regarded as the division between free and slave states before the Civil War. The Bank Road (Rt. 40) connects at Cumberland to the National Road, the nation's first federally funded highway, linking the population east with the sparsely settled Midwest. The section spanning the northern part of Green Ridge was constructed around 1821. The Civilian Conservation Corps (CCC) worked nationwide during the Great Depression on natural resource conservation projects such as planting trees, fighting forest fires, and building roads on public lands. The CCC camp at 15-Mile Creek was one of three at Green Ridge in the 1930s and 40s.