Hand drawn map of mining claims in the Oro Fino Mining District, in La Plata County, Colorado.
The map is focused on the area around Gains Gulch and Leavenworth Gulch, extending north to Oro Fino Camp.
Based upon the names of the claims, we date the map to circa 1890.
Spanish explorers who visited the La Plata Mountains in the 18th century may have found gold, but mining in the region did not begin until 1873 when placer gold was found along the Animas River near the present site of Durango. In that same year placer gold was discovered along La Plata River. Production during the early years in the La Plata district is not known, but it was probably small. Lode gold was also discovered in 1873, and by the end of 1881 many locations had been made.
The output from lodes was small through 1901, but with the discovery of new deposits in 1902, output increased sharply, and through 1914 annual gold production exceeded $100,000 (5,000 ounces).