Alamo Rent a Car is a car rental agency in the United States. Based in Clayton, Missouri, it has branches across North America, South America, Africa, Europe, and Oceania. Alamo was founded in Florida in 1974.Alamo Rent a Car is a car rental agency in the United States. Based in Clayton, Missouri, it has branches across North America, South America, Africa, Europe, and Oceania. Alamo was founded in Florida in 1974.