Northwestern Bloc of the FARC-EP
The Northwestern Bloc of the Revolutionary Armed Forces of Colombia, also known as the Iván Ríos Bloc has historically been a strong influence in the Medellín and Antioquia regions, and still is today. It has been among the blocs most seriously targeted by former president Álvaro Uribe's defense plan and the Colombian Army's offensive. Due to this, the bloc has been forced to retreat to more remote areas of the countryside and has lost the dominance it once had in the area. The specific divisions of the group are arguable. Because of the current conflict existing in the country, much of the information recovered is conflicting. Some of the believed divisions or "fronts", as they are commonly called, are shown below. Many of these fronts sometimes work together towards a certain mission, while others are further divided into "columns" and "companies" with a smaller number of members. For more general information see FARC-EP Chain of Command.
Commanders
| Alias | Name | Note |
| Isaías Trujillo | Luis Carlos Úsuga Restrepo | Bloc commander. |
| Iván Márquez | Luciano Marín Arango | |
| Jesus Santrich | Seusis Hernández | - |
Columna móvil Mario Vélez
This mobile column is composed of around 300 members. It operates mainly in el Nudo de Paramillo, Yarumal, Valdivia and Anorí.5th Front
Also known as the Antonio Nariño Front, this front is composed by up to 350 combatants and operates mostly in the Urabá region of the Antioquia Department.| Alias | Name | Note |
| Jacobo Arango | Front commander. Killed on January 31, 2012. | |
| Jacobo | Luis Carlos Durango Úsuga | Arrested in 2003. |
| "La Muerte" or "Hermes" | Héctor Elías Úsuga Higuita | Killed in April 2011. |
| "Ramirito" | Ramiro Antonio Montoya Moreno | Ringleader, killed in November 2011. |
9th Front
Also known as the Atanasio Girardot Front, this front is composed 45 to 50 combatants and operates mostly in the Antioquia Department. The Colombian military claims that this front has now been dismantled but NGO Nuevo Arco Iris said in 2012 the front is still active| Alias | Name | Note |
| Danilo | Iván de Jesús Zuluaga | Killed in 2009 |
| Gabriel | Second in command | |
| Salomón | Third in command | |
| Alonso, Chamizo | Tulio Murillo Ávila | Arrested in 2005. |
| Caliche | Virgilio de Jesús Guzmán | Demobilized in 2006. |
| David | Sebastián Hernández Giraldo | Arrested on February 14, 2011. |
| "Elicier" or "El Diablo" | Gabriel Arcangel Galvis Montoya | Second-in-command. Killed on July 16, 2012. |
18th Front
This front is composed by up to 150 combatants and operates mostly in the Córdoba Department.| Alias | Name | Note |
| Manteco | Jóberman Sánchez Arroyabe | |
| Román Ruiz | Front commander |
34th Front
Also known as the Alberto Martínez Front, this front is composed by up to 250 combatants and operates mostly in the Chocó and Antioquia Departments.| Alias | Name | Note |
| Pedro Baracutado | Ancízar García | Commands 34th front |
| El Paisa | Jesús Agudelo Rodríguez | Killed in 2008. |
| Amparo | Killed in July 2010. | |
| Modesto | Ramón Antonio Duarte Borja | Captured in July 2010. |
| Elian | Ran away from FARC with his wife alias "Elizabeth". | |
| Elizabeth | Ran away from FARC with his husband alias "Elian". |
36th Front
This front is composed by up to 160 combatants and operates mostly in the Antioquia Department.| Alias | Name | Note |
| "Ánderson" or "Carranza" | Front commander | |
| Dúber | Rubén Darío Pérez Contreras | Killed in 2008. |
| Argemiro, El Zurdo | Martín Francisco Puerta Henao | Captured in 2005. |
| Tres Pelos | Héctor Alfonso Villalobos | Killed in 2003. |
| Guacharaco | Juan Bautista Peña Serna | Killed in April 2010. |
| Pechi | Demobilized in August 2010. | |
| Jaimes | Demobilized on October 26, 2010. | |
| El Pájaro | Jesús Morales Morales | After being wounded, he handed himself to the army on February 8, 2011. |
| Samper | Alberto Montoya Montoya | Captured by Interpol in April 2011. |
| Shampoo | Financial leader and explosive expert. Killed in August 2011 along with two others guerilleros. |
47th Front
Also known as the Leonardo Posada Pedraza Front, this front is composed by 15 to 90 combatants and operates mostly in the Caldas and Antioquia Departments. The front is, as of 2011, mainly active in the border between southern Antioquia and Caldas, with limited, if any, activity in other departments.| Alias | Name | Note |
| Kadafi | ||
| Karina | Nelly Ávila Moreno | Demobilized in 2008. |
On May 19, 2008, Karina surrendered herself to the Colombian authorities, two weeks after president Uribe guaranteed her safety on her surrender. According to the governor of Antioquia, Luis Alfredo Ramos, she was also urged by her family to surrender.
57th Front
This front is composed by up to 250 combatants, and operates mostly in the Chocó Department.| Alias | Name | Note |
| Benkos | 2d in command. | |
| El Becerro | Commander 57th Front, escaped bombing in 'operation darién' | |
| Silver | Killed on October 3, 2010, in Operation Darien |
58th Front
Also known as the Mártires de las Canas Front, this front is composed by up to 150 combatants and operates mostly in the Antioquia and Córdoba Departments.Jacobo Arenas Urban Front
This urban front is considered FARC's greatest influence in the Medellín region.| Alias | Name | Note |
| Ramiro, Político | Killed in 2006. | |
| Octavio | Rolando Acevedo Muñoz | Killed in 2005. |
Raúl Eduardo Mahecha Front
Operates in Antioquia. In September 2011 this front is believed to have rescued three oil workers who were kidnapped by criminals in August 2011. The guerrillas freed the workers and handed them over the Colombian police.Columns and Companies
The following columns and companies also form part of the Northwestern Bloc:- Company Aurelio Rodríguez: Composed by up to 110 combatants, this company operates in the Risaralda and Caldas Departments and is led by Martín Cruz Vega, alias "Rubin Morro". One of its highest ranking militants, Jesús González Cardona, alias "Osama", was captured in 2007.
- Company Héroes y Mártires del Cairo operates in the Antioquia Department.