The Rough Riders was a nickname given to the 1st United States Volunteer Cavalry, one of three such regiments raised in 1898 for the Spanish–American War and the only one to see combat. The United States Army was small, understaffed, and disorganized in comparison to its status during the American Civil War roughly thirty years prior. Following the sinking of USS Maine, President William McKinley needed to muster a strong ground force swiftly, which he did by calling for 125,000 volunteers to assist in the war. The U.S. had gone to war in opposition to Spanish colonial policies in Cuba, which was then torn by a rebellion. The regiment was also nicknamed "Wood's Weary Walkers" for its first commander, Colonel Leonard Wood. This reflected their dissatisfaction that despite being cavalry, they ended up fighting in Cuba as infantry, since their horses were not sent there with them.

Wood's second in command was former Assistant Secretary of the Navy Theodore Roosevelt, a strong advocate for the Cuban War of Independence. When Wood was promoted to become commander of the 2nd Cavalry Brigade, the regiment became known as "Roosevelt's Rough Riders". That term was borrowed from Buffalo Bill, who called his traveling Western show "Buffalo Bill's Wild West and Congress of Rough Riders of the World."

The original plan called for the regiment to be composed of frontiersmen from the Indian Territory, the New Mexico Territory, the Arizona Territory, and the Oklahoma Territory. However, after Roosevelt joined the ranks, it attracted an odd mixture of Ivy League athletes, glee club singers, Texas Rangers, and Native Americans. All accepted into the regiment had to be skilled horsemen and eager to see combat. The Rough Riders would receive more publicity than any other Army unit in that war, and they are best remembered for their conduct during the Battle of San Juan Hill, though it is seldom mentioned how heavily they outnumbered Spanish soldiers who opposed them. Several days after the Battle of San Juan Hill, the Spanish fleet sailed from Cuba, and in only a few weeks an armistice ending the fighting was signed. Despite the brevity of their service, the Rough Riders became legendary, thanks in large part to Roosevelt's writing his own history of the regiment and the silent film reenactments made years later.