The first Palmer Raid is conducted on the second anniversary of the Russian Revolution. Over 10,000 suspected communists and anarchists are arrested in 23 U.S. cities.

The Palmer raids were a series of raids conducted in November 1919 and January 1920 by the United States Department of Justice under the administration of President Woodrow Wilson to capture and arrest suspected socialists, especially anarchists and communists, and deport them from the United States. The raids particularly targeted Italian immigrants and Eastern European Jewish immigrants with alleged leftist ties, with particular focus on Italian anarchists and immigrant leftist labor activists. The raids and arrests occurred under the leadership of United States Attorney General A. Mitchell Palmer, with 6,000 people arrested across 36 cities. Though 556 foreign citizens were deported, including a number of prominent leftist leaders, Palmer's efforts were largely frustrated by officials at the U.S. Department of Labor, which had authority for deportations and objected to Palmer's methods.