As the biggest irregular army in Colombia, the Revolutionary Armed Forces of Colombia (Fuerzas Armadas Revolucionarias de Colombia - FARC) have long operated in various regions of the country in search of resources to fund their insurgency. They agreed to end their 52-year war against the government in August 2016, as part of a peace process that began in 2012. The FARC are the oldest and most important guerrilla group in the Western Hemisphere. They have long financed their political and military battle against the Colombian government through kidnapping, extortion and participating in the drug trade on various levels.
The Rastrojos were born out of the powerful Norte del Valle drug cartel and rose to become one of the most powerful transnational criminal syndicates in Colombia, until their top leadership surrendered or was captured in 2012.
The government of Colombia and the country's largest remaining guerrilla group have agreed to a bilateral ceasefire, but the rebels' lack of unity may make enforcement difficult.
The United Self-Defense Forces of Colombia (Autodefensas Unidas de Colombia - AUC) was a coalition of right-wing death squads that used the conflict to camouflage their illicit economic activities. These included drug trafficking, displacement, kidnapping, and extortion. The AUC once operated in two-thirds of the country with approximately 30,000 soldiers.
The Urabeños -- also known as Clan Usuga -- are one of the most ambitious, ruthless and aggressively expansionist of Colombia's drug trafficking organizations. One of a number of groups made up of former mid-level paramilitary leaders, they are one of the last Colombian criminal groups with a truly national presence.
The Norte del Valle Cartel (NDVC) emerged out of the breakup of the infamous Cali Cartel to became the wealthiest and most powerful Colombian drug trafficking organization of its day. However, for much of its lifespan the group was wracked by paranoia, divisions and treachery, and in its later years operated more as a network of competing factions than a coherent and cohesive group. The protracted dissolution of the cartel that began in 2007 gave rise to several newly independent criminal organizations, including the Rastrojos, which would go on to become one of the most influential of Colombia's next generation of drug trafficking organizations. According to FBI estimates, at its peak the cartel was responsible for 60 percent of the cocaine reaching the United States.