Breckenridge, Colorado is a historic gold mining town and was one of the most productive gold mining regions in the state during the 19th century. The gold deposits in the area were primarily found in placer deposits, which are formed by the erosion and transportation of gold-bearing material by water. The most productive placer deposits in the Breckenridge area were found in the Blue River and its tributaries, including French Creek (where Country Boy Mine is located today), Illinois Creek, and The Swan River. These placer deposits were mined using various methods such as panning, sluicing, and dredging. Additionally, lode deposits (veins of gold in hard rock) were also found in the area and were mined by underground methods such as hard rock mining.