Founded in the nineteenth-century South, the Ku Klux Klan attracted new adherents in the early 1900s, as increasing numbers of immigrants brought their own ethnic and religious traditions to the nation's cities and towns. Often referred to as the Second Ku Klux Klan, the new iteration adopted the robes and beliefs of the predecessor, while expanding the scope of prejudice to include immigrant and religious groups. At Klan rallies, speakers warned that "real" Americans were losing control of the country. Newcomers were taking over local government, the police, and the schools. The Klan claimed that foreigners, especially Catholics and Jews, would soon outnumber white, Anglo-Saxon Protestants. Something, the Klan insisted, had to be done about it.

In the early 1920s, Klan meetings and cross-burnings began to occur with some regularity in small towns in eastern and central Massachusetts. Both secret and public Klan meetings were held in Worcester County towns, including Berlin, Holden, Shrewsbury, Marlborough, Upton, Paxton, Charlton, West Brookfield, and Spencer.

Many New Englanders were receptive to the Klan's message. Workers in Maine, New Hampshire, and Vermont resented the influx of French Canadians, who were not only Catholic but also willing to accept lower wages than native-born workers. In Massachusetts and Rhode Island, anti-Irish prejudice reappeared as Irish Americans gained political power. Anti-Italian sentiment was also prevalent throughout southern New England.

The city of Worcester became a center of Klan activity. In 1923 the Klan launched a major recruiting drive there. At one rally at Mechanic's Hall, the city's largest public venue, speakers inflamed the audience with claims that Catholics were overtaking the city's government, police force, and positions as public school teachers. "When Worcester folks see 20,000 to 30,000 Klansmen in uniform parading the streets of Worcester, and this time isn't far off, " one speaker predicted, "then we will definitely be ready for action."

The peak of Klan activity in the city took place on October 19, 1924, during the largest gathering of the Ku Klux Klan ever held in New England. Klansmen in sheets and hoods, new Knights awaiting a mass induction ceremony, and supporters swelled the crowd at the Agricultural Fairgrounds to 15,000. The KKK had hired more than 400 "husky guards," but when the rally ended around midnight, a riot broke out. Klansmen's cars were stoned, burned, and windows smashed. KKK members were pulled from their cars and beaten. Klansmen called for police protection, but the situation raged out of control for most of the night.

The Klan rally in Worcester in the fall of 1924 and the reaction to it were part of a national struggle over who could be considered truly American. Many native-born people were fearful about what they viewed as a decline in traditional American values, rooted in the Protestant religion and Anglo-Saxon culture. The anti-Klan forces were determined to protect the rights of religious and ethnic minorities. The violence at the "Klanvocation" in Worcester led to a slow decline in Klan membership in the area and no further public events were held.