Foreign Policy in Focus reprinted a piece on 15 April 2014 titled "AFRICOM Goes to War on the Sly" by Nick Turse, managing editor of TomDispatch.com. Although the title of the article in my view overstates the role of the U.S. military in Africa, the piece does pull together wide ranging, if limited, U.S. military activity in Africa.
The author concludes that the U.S. military is "pivoting to Africa." (As compared to earlier years, yes; as compared to Asia, no.) He notes the the U.S. military averages far more than a mission a day on the continent, conducting operations with almost every African military force, in almost every African country, while building or building up camps, compounds, and contingency security locations. While the author identifies U.S. military activity in a significant number of African countries, the overwhelming majority of Africa's 54 countries are not mentioned in the article.