Ludlow Massacre — attack by Colorado National Guard and mine camp guards on striking coal miners
The deadliest strike incident in U.S. history, it galvanized labor reform and led to child labor laws and the eight-hour workday.
Key Facts
- Date
- April 20, 1914
- Deaths at Ludlow
- Approximately 21 people
- Total strike deaths
- 69 to 199 people
- Striking miners in tent colony
- Roughly 1,200 people
- Retaliatory front length
- 225 miles
- National Historic Landmark designated
- January 16, 2009
By the Numbers
Location
Cause → Event → Consequence
In September 1913, members of the United Mine Workers of America launched a general strike against Colorado Fuel and Iron Company over poor labor conditions in southern Colorado coal mines. Striking miners and their families relocated to tent colonies, including one at Ludlow, as tensions between workers, company guards, and the Colorado National Guard escalated over the following months.
On April 20, 1914, soldiers from the Colorado National Guard and private guards employed by CF&I attacked the Ludlow tent colony, which housed roughly 1,200 striking miners and their families. The assault killed approximately 21 people, predominantly women and children, making it the deadliest single incident of the Colorado Coalfield War.
The massacre sparked ten days of armed reprisals across Colorado, with miners attacking anti-union operations along a 225-mile front until federal troops intervened on April 29. Public outrage prompted a congressional investigation whose 1915 report advanced child labor protections and the eight-hour workday. The Ludlow site was designated a National Historic Landmark in 2009 and remains owned by the United Mine Workers of America.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Side B
1 belligerent