U.S. Strategic Nuclear Forces: Background, Developments, and Issues [August 8, 2017] [open pdf - 995KB]
"During the Cold War, the U.S. nuclear arsenal contained many types of delivery vehicles for nuclear weapons, including short-range missiles and artillery for use on the battlefield, medium-range missiles and aircraft that could strike targets beyond the theater of battle, short- and medium-range systems based on surface ships, long-range missiles based on U.S. territory and submarines, and heavy bombers that could threaten Soviet targets from their bases in the United States. The short- and medium-range systems are considered non-strategic nuclear weapons and have been referred to as battlefield, tactical, and theater nuclear weapons. The long-range missiles and heavy bombers are known as strategic nuclear delivery vehicles."
CRS Report for Congress, RL33640
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html