Paul Robeson rally
According to Quill Pettway, the last rally, in Detroit's downtown Cadillac Square, drew 60,000 people. "Regardless of race, creed or color, they came to hear Robeson, Walter Reuther, former City Council President Erma Henderson," among others.
According to an article published for the occasion by the UAW, Irving Bluestone, Walter Reuther’s top aide during the early 1960s, and later a UAW vice president, said, “The UAW did everything possible to support King and the civil rights movement. When King began planning the Walk to Freedom march, he wanted as many unionists as possible marching with him.”
“To help him, Reuther gave King the use of an office in Solidarity house, UAW headquarters,” Bluestone said. “King used it while he was planning the march in Detroit and the March on Washington that took place the next month.”
Detroit’s 1963 march was enormous, with 200,000 people led by King and Reuther marching down Woodward Avenue. It ended at Cobo Hall in downtown Detroit with King delivering a rousing speech. One person who was at the original march said that it was tremendous to see so many Detroiters making a stand for civil rights. “We waited for hours to get in the march,” she said. “By the time we got down to Cobo Hall, we couldn’t get in, there were so many people.” 
March on Washington - key four
According to Democratic Left, Winter 2012, page 10, four democratic socialists organized the 1963 March on Washington – A. Philip Randolph, Bayard Rustin, Martin Luther King, Jr., and UAW president Walter Reuther.
Socialist Debs award
Every year since the mid 1960s the Indiana based Eugene V. Debs Foundation holds Eugene Debs Award Banquet in Terre Haute, to honor an approved social or labor activist. The 1968 honoree, was Walter Reuther.