The bridge was the site of a major event in Milwaukee's Civil Rights Movement. In the 1960s, the city did not have an open-housing ordinance in place and banks, real estate agents, and white neighborhood organizations took steps to intentionally restrict housing options for African Americans. This led to the development of segregated housing and ultimately divided the city into the north side, which was primarily comprised of African Americans, and a white-dominated south side. Father James E. Groppi, a leader in Milwaukee's Civil Rights Movement, called the 16th Street Viaduct the Mason-Dixon line that separated the two halves of the city.
With Groppi as a mentor and leader, the march was only possible through the support of the NAACP Youth Council. Members of the organization, with the help of adult leaders in the NAACP, staged a march down the length of the 16th Street Viaduct. The marchers traveled from Clybourn Ave to Kosciuszko Park at S. 10th St. and W. Lincoln Ave on the south end of the bridge. With a permit in hand to have a picnic at Kosciuszko Park, 200 demonstrators marched down the bridge on August 28, 1967.
A crowd of counter-protesters met the demonstrators along the way and at the Park, where the group was surrounded by approximately 5,000 people and 125 police officers armed with riot gear. The Milwaukee Journal reported that
the shouts of the spectators and the marchers set up a din so loud that
a person had to shout to be heard two feet away,
Several spectators held up a Confederate battle flag.1
Fights ensued as the protestors made their way back to the bridge, and sixteen people were arrested along with two serious injuries. A second march was held again the next evening, with 13,000 counter-protesters armed with eggs, bottles, rocks, firecrackers and beer cans, according to the Milwaukee Sentinel. That night saw more than twenty injuries and 45 arrests.
These marches led the way to more than 200 marches and demonstrations across Milwaukee to demand an open-housing ordinance. In December of 1967, the ordinance was enacted. In 1988 the bridge was renamed the James E. Groppi Unity Bridge in commemoration of this important event.