What was the longest speech Martin Luther King Jr give?

The longest speech Martin Luther King Jr. delivered was at the 1965 Selma to Montgomery march, known as the "How Long, Not Long" speech. It lasted approximately 15 minutes and addressed the struggle for voting rights and racial equality. King emphasized the urgency of the Civil Rights Movement and the need for justice, making a powerful call for action and perseverance in the face of oppression. This speech was pivotal in galvanizing support for the Voting Rights Act of 1965.