This small but important map documents the first commercial discovery of oil west of the Mississippi River in Canon City in 1862. Subsequent drilling led to the development of the prolific Florence Oil field shortly after the publication of this map and an accompanying report by Magnus Ihlseng (not present here). Ihlseng’s report explained the features on the map and details of the past and current locations of wells. The well drilled in 1880 designated as “2” on the map is commonly referred to as the first in the Florence Oil Field although it did not produce and was abandoned. Ihlseng suggested that the oil potential encompassed a broader area and that further drilling would be successful. He was correct. The full report is available online here.