 In early May 1970 , protests began on the campus of Kent State University over the United States ' invasion of Cambodia in the Vietnam War . These protests and demonstrations , which included rioting in downtown Kent on May 2 , culminated in the Kent State shootings on May 4 , 1970 , where four students were killed and nine were wounded by the Ohio Army National Guard . Several memorials have been placed at the site over the years and commemorations have been held annually since 1971 . In 2010 the entire site was listed on the National Register of Historic Places . Also during the late 1960s and into the 1970s , construction of Haymaker Parkway , completed in 1975 , brought changes to the city 's layout while eliminating ongoing problems with traffic congestion and blocked rail crossings . 
