Why martin luther king jr mention alabama mississippi and georgia

These three southern states were mentioned by Martin Luther King, Jr. in his speech at the Lincoln Memorial in Washington D.C. on August 28, 1968 during the march to Washington.  In his speech, King outlined the sufferings and struggles of Africans during the civil rights movement.  Despite being free from slavery for 100 years, African Americans are still treated poorly.  Many in the South are being persecuted and harassed. He mentioned these  three states because the level of brutality and racism against blacks have been the worse yet he dreams that one day blacks and whites will come together as equals and that this conflict will one day come to an end.