Colombia is the world’s #1 producer of cocaine, according to both the U.S. State Department and the United Nations’ office on Drugs and Crime.
While nobody exactly knows how much coca is cultivated and how much cocaine is produced and subsequently exported, both the United Nations and the United States make annual estimations of the size of the illicit industry.
In 2014, Colombia had 69,000 hectares of coca cultivation according to the United Nations and 112,000 hectares, according to the United States. According to the United Nations, this coca production would have produced 487 tons of cocaine.
Coca cultivation in Colombia in hectares
Coca is grown across Colombia, but most intensely in areas where there has been a chronic state abandonment, either due to dysfunctionality of the state or because of heightened presence by leftist rebel groups like the FARC or ELN who tax coca growers and in some areas buy the leafs to turn them into coca paste.
2014 coca cultivation by province
In its annual report, The United Nations Office on Drugs and Crime (UNODC) provides relatively accurate maps on where the density of coca crops is highest.
Coca cultivation density in 2014
UNODC 2014 report (PDF) (United Nations)
2015 International Narcotics Control Strategy Report: Colombia (United States)