Why did Hamburg change its name to North Augusta shortly after World War I began? *

the United States government made them change the name
anti-German sentiment and changing many things with German heritage
guilt over the Hamburg Massacre
they were purchased by Augusta

The Hamburg Massacre (or Red Shirt Massacre or Hamburg riot) was a key event in the African American town of Hamburg, South Carolina in July 1876, leading up to the last election season of the Reconstruction Era. It was the first of a series of civil disturbances planned and carried out by white Democrats in the majority-black Republican Edgefield District, with the goal of suppressing black voting, disrupting Republican meetings, and suppressing black Americans civil rights, through actual and threatened violence.[1]

Beginning with a dispute over free passage on a public road, the massacre was rooted in racial hatred and political motives. A court hearing attracted armed white "rifle clubs," colloquially called the "Red Shirts". Desiring to regain control of state governments and eradicate the civil rights of black Americans, over 100 white men attacked about 30 black servicemen of the National Guard at the armory, killing two as they tried to leave that night. Later that night, the Red Shirts tortured and murdered four of the militia while holding them as prisoners, and wounded several others. In total, the events in Hamburg resulted in the death of one white man and six black men with several more blacks being wounded. Although 94 white men were indicted for murder by a coroner's jury, none were prosecuted.

The events were a catalyst in the overarching violence in the volatile 1876 election campaign. There were other episodes of violence in the months before the election, including an estimated 100 blacks killed during several days in Ellenton, South Carolina, also in Aiken County. The Southern Democrats succeeded in "redeeming" the state government and electing Wade Hampton III as governor. During the remainder of the century, they passed laws to establish single-party white rule, impose legal segregation and "Jim Crow," and disenfranchise blacks with a new state constitution adopted in 1895. This exclusion of blacks from the political system was effectively maintained into the late 1960s.