The Freedom Summer, also referred to as the Mississippi Freedom Project, took place in the summer of 1964, when civil rights groups such as the Congress of Racial Equality (CORE) and SNCC (Student Non-violent Coordinating Committee) tried to register African-Americans, who were largely disenfranchised, to vote in the state. The civil rights workers were harassed by groups such as the KKK, and two civil rights workers from New York--Michael Schwerner and Andrew Goodman--and one local activist--James Chaney--were murdered in June of 1964 in Philadelphia, Mississippi. SNCC, an offshoot of Dr. Martin Luther King's Southern Christian Leadership Conference (SCLC), involved students across the country, African-American and white, in advocating for civil rights through sit-ins, protests, voter registration drivers, and other forms of activism.
The Mississippi Freedom Democratic Party (MFDP) was a political party organized to represent Mississippi in 1964 as an alternative to the Mississippi Democratic Party, which was all white. The MFDP, which included African-American activists, went to the 1964 Democratic National Convention and sought to be seated at the convention. The party, represented by Fannie Lou Hamer and others, were offered two at-large seats on the convention floor, but they left the convention rather than submit to not receiving regular seats on the floor.
The Voting Rights Act of 1965 was passed under President Lyndon B. Johnson. It was intended to prevent discrimination in voting and to enforce the right of African-Americans and other racial or ethnic minorities to vote under the 14th and 15th Amendments to the Constitution. Though the law is still in effect, the Supreme Court gutted some of it's key provisions in a controversial 2013 ruling.