- Please see "Lieutenant Colonel" for other countries which use this rank
In the United States Army, Air Force, and Marine Corps, a lieutenant colonel is a field grade military officer rank just above the rank of major and just below the rank of colonel. It is equivalent to the rank of commander in the other uniformed services.
The pay grade for the rank of lieutenant colonel is O-5. The insignia for the rank consists of a silver oak leaf, with slight stylized differences between the Army/Air Force version and the Navy/Marine Corps version.
The rank of lieutenant colonel was first created during the Revolutionary War, when the position was held by aides to Regiment Colonels, and was sometimes known as "Lieutenant to the Colonel." The rank of Lieutenant Colonel had existed in the British Army since at least the 16th century.
During the 19th century, lieutenant colonel was often a terminal rank for many officers, since the rank of "full colonel" was considered extremely prestigious reserved only for the most successful of officers. Upon the outbreak of the Civil War, the rank of Lieutenant Colonel became much more common and was used as a "stepping stone" for officers who commanded small regiments or battalions and were expected, by default, to be promoted to full Colonel once the manpower of a regiment grew in strength. Such was the case of Joshua Lawrence Chamberlain, who commanded a Maine Regiment as both a lieutenant colonel and later as a colonel.
After the Civil War ended, those officers remaining in the U.S. armed forces found lieutenant colonel to again be a terminal rank, although many lieutenant colonels were raised to higher positions in a brevet status. Such was the case with George A. Custer, who was a lieutenant colonel in the regular army, but held the brevet rank of major general. 
The 20th century saw lieutenant colonel in its present day status although, during the 1930s, many officers again found the rank to be terminal as the rank of colonel was reserved for only a select few officers. Such was not the case during World War II, when lieutenant colonel became one of the most commonly held officer ranks in the U.S. Army.
In the United States Army, a lieutenant colonel typically commands a battalion-sized unit (300 to 1,000 soldiers), with a Command Sergeant Major as principal NCO adviser. A lieutenant colonel may also serve as a brigade or task force Executive Officer, or principal staff officer, S-1 (administration and personnel), S-2 (intelligence), S-3 (operations), S-4 (logistics), S-5 (civil/military affairs), or S-6 (computers and communications). Usage of "The S-n" may refer to either a specific staff section or the staff officer leading a section. Lieutenant Colonels may also be junior staff at a variety of higher echelons.
In the United States Air Force, a lieutenant colonel is generally a director of operations or a squadron commander in the operations group, a squadron commander in the mission support and maintenance groups, or a squadron commander or division chief in a medical group. Lieutenant colonels may also serve on general staffs and may be the heads of some wing staff departments.
In the 21st century U.S. military, the rank of lieutenant colonel is usually gained after 16–22 years of service as an officer. As most officers are eligible to retire after 20 years active service, it is the most common rank at which career officers retire.
The insignia for the rank consists of a silver oak leaf, with slight stylized differences between the Army/Air Force version and the Navy/Marine Corps version.
While written as "Lt. Colonel" in orders and signature blocks, as a courtesy, lieutenant colonels are addressed simply as "Colonel" verbally and in the salutation of correspondence. The U.S. Army uses the three letter abbreviation "LTC." The U.S. Air Force and United States Marine Corps use the abbreviations "Lt Col" and "LtCol" (note the space) respectively.
The U.S. Government Printing Office recommends the abbreviation "LTC" for U.S. Army usage and "Lt. Col." for Air Force and Marine Corps usage. The Associated Press Stylebook recommends the abbreviation "Lt. Col." for the Army, Air Force, and Marine Corps.
Slang terms for the rank historically used by the U.S. military include "light colonel", "short colonel", "light bird", "half colonel", "bottlecap colonel" (referring to the silver oak leaf insignia), and "telephone colonel" (from self-reference as "colonel" when using a telephone).
Famous American lieutenant colonelsEdit
- Robert L. Bacon (US Army)
- Scott Brown (Army National Guard)
- Aaron Burr (Continental Army)
- Joshua Chamberlain (US Army)
- Robert G. Cole (US Army)
- Jerry Coleman (United States Marine Corps)
- David P. Cooley (US Air Force)
- George A. Custer (US Army)
- Rick Francona (US Air Force)
- John C. Fremont (US Army)
- Gus Grissom (US Air Force)
- Anthony B. Herbert (US Army)
- Gus Kohntopp (Air National Guard)
- Oliver North (US Marine Corps)
- Ralph Peters (US Army)
- Rob Riggle (US Marine Corps)
- Ronald Speirs (US Army)
- Michael Strobl (US Marine Corps), portrayed by Kevin Bacon in the HBO movie Taking Chance.
- William Travis (Texas Militia)
- Matt Urban (US Army)
- John Paul Vann (US Army)
- Edward Higgins White (US Air Force)
- Earl Woods (US Army)
- Philip Corso (US Army)
- Christopher B. Howard (US Air Force)
- Lt. Col. Henry Blake of the film and television series M*A*S*H, portrayed by Roger Bowen and McLean Stevenson, respectively.
- Samantha Carter was promoted to this rank in the eighth season of the television series Stargate SG-1 (portrayed by Amanda Tapping).
- John Sheppard was promoted to this rank in the second season of the television series Stargate: Atlantis (portrayed by Joe Flanigan).
- Lt. Col. Cameron Mitchell of the television series Stargate SG-1, portrayed by Ben Browder.
- George Peppard famously played Lt. Colonel John "Hannibal" Smith on The A-Team. Although he was usually referred to as a Colonel, his rank was clarified in many episodes as Lt. Colonel.
- Lt. Col. Bill Kilgore in the 1979 film Apocalypse Now, portrayed by American actor Robert Duvall.
- Lt. Col. Robert Neville of the 2007 film I Am Legend, portrayed by American actor Will Smith. The movie is based on the book of the same name, I Am Legend, from 1954. The 2007 film version is a remake of the 1971 film The Omega Man, in which Robert Neville, portrayed by Charlton Heston, is one of few remaining survivors of a hellish germ-warfare doomsday.
- Lt. Col. Sarah MacKenzie was promoted to this rank in the fifth season of the television series JAG, portrayed by Catherine Bell.
- Al Pacino portrayed Lieutenant Colonel Frank Slade in the 1992 film Scent of a Woman.
- Sean Connery portrayed Lt. Col. Alan Caldwell in the film The Presidio in 1988
- Lt. Col. Joan Burton of the Lifetime television series Army Wives, portrayed by Wendy Davis. The series is based on the book of the same name, Army Wives by Tanya Biank.
- Lt. Col. Thomas Devoe of the movie The Peacemaker, portrayed by George Clooney.
- Lt. Col. Nathaniel Serling of the movie Courage Under Fire, portrayed by Denzel Washington.
- Lt. Col. John Casey, one of the protagonists in the NBC series Chuck
- Lt.Col. James "Rhodey" Rhodes, portrayed by Terrence Howard and Don Cheadle in "Iron Man (film)" and "Iron Man 2" respectively.