From September 1913 until late April 1914, much of Las Animas County was embroiled by the Colorado Coalfield War, which saw up to 12,000 pro-United Mine Workers of America strikers engaged in both peaceful and violent confrontations with the Rockefeller-owned Colorado Fuel & Iron Company, other mining outfits, strikebreakers, and the Colorado National Guard. On 29 October 1913, the Aguilar post office and several other town structures were destroyed in an arson attack related to the strike. The National Guard arrested several strikers over the attack and handed them over to the federal U.S. Marshal Service.