During 1961, who were the protesters that traveled through Alabama and Mississippi in an effort to stop segregation nonviolently?

They were known as the Freedom RIders.

Explanation:

Their main goal was to end segregation but they protested in a local level by boycotting busses, highways, trains and bus stops. They were led by Fred Shuttlesworth, who became a minister in Alabama. Fought to end segregation.

Opportunity Riders were gatherings of white and African American social equality activists who took an interest in Freedom Rides, transport trips through the American South in 1961 to fight isolated transport terminals.