This will be the president's second trip to Africa. And the speech is expected to lay out his position on the issues he will raise with African leaders.
White House National Security Advisor Stephen Hadley says the trip will underscore America's commitment to the region - starting with the efforts to fight dangerous diseases and foster economic growth and development.
"There is more hope in Africa and the American people can be proud that many of our innovative programs are making a real difference," he said.
The president's travels will take him to Benin, Tanzania, Rwanda, Ghana and Liberia. Along the way, he will visit medical facilities, job training centers, and small businesses.
Hadley says the president's talks with leaders in these countries will also focus on efforts to resolve ongoing conflicts in Africa, including the crisis in Kenya. He says the White House considers the situation in Kenya to be a matter of great concern and a great tragedy.
"Unfortunately, what is happening in Kenya is a step backward," he added. "What needs to happen is pretty clear. We have been very actively engaged in our diplomacy there in supporting what Kofi Annan is doing. The first step is for the parties to agree to stop the violence, the second step is to facilitate humanitarian assistance, and third, work out a power-sharing arrangement."
During a session with reporters, Hadley indicated the president will mention Kenya in Thursday's address at the National Museum of African Art. He indicated there will also be comments about the bloodshed in Sudan's Darfur region, noting there has been progress there, but the president believes it has been far too slow.