In the 1930s, the Confederation of Mexican Workers organized field workers in California's Imperial Valley, with over 2,700 members. However, the local sheriff arrested union leaders on false charges and suppressed the union. The Communist Cannery and Agricultural Workers Industrial Union distributed leaflets promoting organization and strikes among agricultural workers. They played a role in 24 strikes in 1933, including the largest agricultural strike in US history involving 10,000 cotton pickers across 500 miles.