The Eastern Bloc of the Revolutionary Armed Forces of Colombia, from September 2010 known as Bloque Comandante Jorge Briceño, in honour of the slain guerrilla leader,^[1] was considered to be the strongest military faction of the guerrilla group. It was divided into groups of 50–400 combatants in each group, which patrolled and controlled different areas of Colombia's Eastern and Central-Eastern territory, as well as helped to carry out the killings, taxation, and arrests necessary to advance the organization's financial and political goals.

The specific divisions of the group are arguable. Some of the believed divisions or 'fronts', as they were commonly called, are shown below. Many of these fronts sometimes worked together towards a certain mission, while others were further divided into 'columns' and 'companies' with a smaller number of members. For more general information see FARC Chain of Command.

Commanders

This group of commanders was called the "EMBO" (Estado Mayor del Bloque Oriental).

1st Front

Also known as the Armando Ríos Front, it was composed of around to 400 people.^[13] It operated mostly in the Guaviare Department.

7th Front

Also known as the Jacobo Prías Alape Front, it was composed of up to 400 people. It operated mostly in the Meta Department.

10th Front

Also known as the Guadalupe Salcedo Front, it was composed of up to 300 people.^[19] It operated mostly in the Arauca Department.

Several police officers infiltrated one of the FARC’s 10th front camp in early 2008, preparing an attack on the camp by a police squadron. The attack came on July 29, killing 'Jurga Jurga', FARC commander and friend of FARC head ‘Mono Jojoy’. The ground offensive was follow by an airforce attack, killing 20 guerrillas, unofficial sources said. On October 22, 2011, members of the front killed 10 Colombians soldiers in an ambush in Arauca.^[20] On March 17, 2012, alleged members of the 10th front killed 11 members of the Colombian army. Security forces launched an offensive few days after the attack: on March 20, 3 alleged member of the FARC are killed and 4 captured by the army. On March 21, 33 FARC members were allegedly killed and 5 others captured.^[21]

16th Front

Also known as the Jose A. Paez Front, it was composed of up to 300 people. It operated mostly in the Vichada Department.

22nd Front

Also known as the Simón Bolívar Front, it was composed of up to 120 people. It operated mostly in the Cundinamarca Department.

26th Front

Also known as the Hermogenes Maza Front, it was composed of up to 130 people. It operated mostly in the Meta Department. As of 2011 this front operated in La Uribe, Vista Hermosa, La Macarena and other municipalities.^[35][36]

27th Front

It was composed of up to 500 people and operated mostly in the Meta Department.

28th Front

Also known as the José María Córdoba Front, it was composed of up to 120 people. It operated mostly in the Casanare and Boyacá Departments.

31st Front

This front was composed by up to 120 combatants and operated mostly in the Meta Department. Its activity diminished notoriously after its head, Duván Alberto Cartagena, was captured.^[36]

38th Front

Also known as the Ciro Trujillo Castaño Front, it was composed of up to 100 people. It operated mostly in the Casanare and the Boyacá Departments.

39th Front

Also known as the Joaquin Ballen Front, it was composed of anything between 40 and 300 people. It operated mostly in the Vichada Department. The front was led by El Cadete.^[46]

40th Front

Also known as the Jacobo Arenas Front, it was composed of up to 350 people. It operated mostly in the Meta Department.

42nd Front

Also known as the Combatientes de Cundinamarca Front, it was composed of up to 110 people. It operated mostly in the Cundinamarca Department.

43rd Front

It was composed of up to 300 people and operated mostly in the Meta Department.

44th Front

Also known as the Antonio Ricaurte Front, it was composed of up to 350 people. It operated mostly in the Meta Department.