Forward observers in the U.S. military are artillery observers who carry the Military Occupational Specialty designator of 13F in the United States Army and 0861 in the United States Marine Corps. They are officially called Joint Fire Support Specialists in the U.S. Army and Fire Support Men in the U.S. Marine Corps. They are colloquially known as FiSTers, regardless of whether they are members of a FiST (Fire Support Team). The Battalion Fire Support Officer (FSO) is the Officer in Charge of a Battalion Fire Support Element.
Forward Observers in the U.S. Army hold the Military Occupational Specialty of 13F for enlisted and 13A for officers designating them as members of the Field Artillery corps. After completion of Basic Combat Training enlisted soldiers attend a thirteen-week course on the fundamentals of Call-For-Fire techniques as well as general field craft and small unit tactics at Fort Sill, Oklahoma. From there those being assigned to Airborne units, most notably the 82nd Airborne Division, 173rd Airborne Brigade, and 75th Ranger Regiment will attend the United States Army Airborne School after the completion of training at Ft. Sill. Additionally Ranger School is open to both enlisted and officers serving as Forward Observers. Members of Forward Observer teams are required to attain and maintain a Secret security clearance due to the requirement for Forward Observers to be aware of not only the mission of their own unit but of other U.S. and allied units in the same operating area. Officers are referred to as Fire Support Officers (FSO) while enlisted troops hold the title of Forward Observers.
Once training is complete members are assigned to a Forward Observer Platoon generally part of a Headquarters and Headquarters Company inside a larger Infantry, Cavalry, Armor, or Artillery Battalion. Observer teams are expected to be able to move, communicate, interact and carry out missions as members of these units with a high level of proficiency in addition to their responsibilities as Forward Observers. Observers must be able to work independently for long periods of time and, because the clandestine nature of their work and their frequent placement on or behind enemy lines, the ability to operate with minimal support is of great importance as some missions can often last for days or weeks. Currently three methods of directing artillery fire are taught in the U.S. Army. The first and most common is called a Grid Mission where artillery fire to directed based on the map grid coordinate of the target based on a standard map. The second is Shift From Known Point where artillery based on his direction and distance from a fixed, pre-established geographic or man made point. The third and least common is Polar where the observer gives their current grid location and provides distance and direction to the target. This is typically unpopular due to the FDC confusing the observer's location as the target.
Combat Observation Lasing Teams(COLTs) are a sub-specialization within the Army's 13F career field which train in the directing of long range fire such as rocket assisted artillery or GPS guided munitions like the 155mm EXCALIBUR series weaponry. They have a secondary spotting/reconnaissance capability and are trained to operate with other unconventional forces such as sniper and scout teams for long periods of time with minimal support. These COLT teams are now uncommon and rarely used.
Since 2003 the U.S. Army has also used the RQ-7B Shadow Unmanned Aircraft, flown by soldiers in the 15W MOS, in Iraq and Afghanistan for artillery correction, close air support and reconnaissance..
With the need for coordinated indirect-fire support control at higher levels, Fire Support Specialists are also assigned to the “Fire Support Element,” at the battalion level, and as the "Fires" section of the Operations Staff from brigade/regiment level through to the corps level.
Field Artillery Forward Observer 1189
The primary duties of the 1189 was "Direct the fire of an artillery unit from a forward position. Observes shell bursts and adjusts fire by forward observation or computation methods; consults with commanders of supported unit in determination of appropriate artillery targets, normal barrage, and zones of defense; trains personnel in procedures of artillery operation; organizes observation posts; sets up and maintains communication systems."
U.S. Marine Corps
The requirements for USMC observers are nearly identical to their Army counterparts. They attend training at Ft. Sill, are required to obtain a secret security clearance, and are generally assigned as specialist members of larger combat units or specialized units like Air Naval Gunfire Liaison Company. The main difference is USMC observers are required to show a higher level of proficiency in directing naval gunfire, a skill which their Army counterparts are only required to have a general familiarity with.
The U.S. Navy has a small corps of Naval Gunfire Liaison Officer trained to provide observation and correction of naval gunfire in support of Army and Marine Corps ground units during amphibious and coastal operations. As early as 1921 the United States Marine Corps identified Naval Gunfire as one of the six key elements for amphibious operations. The trajectory of high velocity naval artillery was significantly different from field artillery howitzers typically used for gunfire support. Infantry officers were surprised by the inability of flat trajectory naval guns to hit targets behind low hills; and the relatively wide distribution of fall of shot along the axis of fire sometimes endangered friendly troops behind or in front of the target. Shells intended to penetrate armored ships produced a relatively small damage radius against unfortified targets; and shipboard observation devices designed to observe shell splashes at sea were unable to determine whether their shells were striking intended shore targets. Although Marine Corps officers who have served aboard warships are more familiar with naval artillery, Army officers without such experience are often in positions requiring gunfire support during amphibious landings. Naval officers familiar with shipboard guns are able to advise infantry officers ashore concerning the capabilities of naval artillery to engage specific targets. The naval officer's familiarity with shipboard communications systems enables him to translate the infantry objectives and fall of shot observations to the appropriate shipboard personnel for effective engagement of targets. The tentative manual of 1934 became Fleet Training Publication 167 in 1938; and the Army issued a field manual with virtually identical text in 1941 The use of Naval Gunfire Support reached its peak during WWII with the numerous amphibious landings, to include a small number who completed the Army's elite Airborne School and parachuted into Normandy to provide gun fire support for paratroopers during the D-Day landings.
In the modern age NGLOs are assigned to a Marine Artillery Battalion or Marine Artillery Regiment to assist in providing naval gunfire support. When deploying as part of a Marine Expeditionary Unit, the NGLO is typically attached to the Operations Section (S-3) of the Ground Combat Element and is responsible for a Shore Fire Control Party consisting of RT Operators and Forward Observers.
While NGLOs are trained to spot Naval Gunfire, their primary responsibilities are in the Fire Support Coordination Center to plan and coordinate naval gunfire with other firing agencies (artillery, close air support, and mortars) in conjunction with the Fire Support Coordinator and Fire Support Team Leaders, and advise him on its employment. NGLOs can also be assigned to Air Naval Gunfire Liaison Companies (ANGLICO), or the various Marine Expeditionary Force or Division Headquarters staff.
Specific training consists of the Naval Gunfire Liaison Officer Course, a five-week resident course taught in Coronado, California. NGLOs assigned to ANGLICO units may receive further training as Joint Terminal Attack Controllers (JTACs) at the discretion of the assigned unit and are Jump qualified.
U.S. Air Force
Although the U.S. Air Force has no formal forward observer training of its own, members of the Special Tactics community are generally required to have a basic familiarity with techniques of call for fire and artillery spotting in addition to their normal duties. The closest thing the Air Force has to a Forward Observer is a JTAC, whom specializes in air support. They are also referred to as TACP. 
Joint Fires Observer
The Joint Fires Observer (JFO) course is a two-week course which provides select personnel from all branches of the military with standardized and certified training to engage targets with joint fires through the detailed integration with Terminal Attack Controllers (TACs) and Fire Support Teams (FSTs). Students who graduate this course will be able to request, control, and adjust joint mortar, Field Artillery (FA), and Naval Surface Fire Support (NSFS) systems; provide targeting information for A-10, AC-130, and other Close Air Support (CAS) aircraft, Terminal Guidance Operations (TGO), Initial Terminal Guidance (ITG) operations, SOF gunship call for fire, Close Combat Attack (CCA) and joint fire support planning at the company level. Additionally a JFO is trained in controlling multiple ground and air based fire support assets at the same time, ensuring the different assets are deconflicted by time, lateral or vertical space, or a combination of the two tactics.
JFOs in the Army and Marine Corps are typically officers or enlisted Forward Observers or special operations who are awarded the L7 additional skill identifier, or ASI, is becoming a valued ability to combat brigades headed overseas. The first certifying JFO course was established at Nellis Air Force Base in 2004. It was then moved to Fort Sill in 2006, and also Einsiedlerhof, Germany at the Warrior Preparation Center. The Marines have also established their own JFO course in Quantico, VA.
The JFO course consist of 7 Graded Sim's with numerous Fire Missions and CAS missions. In these SIM’s you will conduct Mortar, Artillery CFF missions, Naval gun CFF, Attack Aviation and SOF CFF mission, CAS with JTAC or FAC(A). Consisting of night optics, laser guided bomb (GBU12) , JDAM (GBU 38), Hellfire, Rockets, with LLDR or just a map, protractor and compass.
Sim 1 Perform an Adjust Fire mission and provide targeting information directly to an aircraft controlled by a TAC for CAS mission using Type 2 control.
Sim 2 Execute visual target marking for CAS.
Sim 3 Execute sensor target marking for CAS.
Sim 4 Conduct call for fire missions. (SOF and Attack Aviation)
Sim 5 Integrate with FAC(A) during CAS mission.
Sim 6 Coordinate CAS target engagement as Non-JTAC.
Sim 7 It is a random mixture of these 6 Sims as the Final evaluation. (1 CFF mission and 2 CAS missions).
After the completion of these SIM's with no more than 3 NO GO's and a passing rate on the written exam of 80 percent or higher, only then are you awarded the L7 and certification approval of JFO ASI.
Notable U.S. military forward observers
- John R. Fox, Medal of Honor recipient (posthumous)
- Jared C. Monti, Medal of Honor recipient (posthumous)
- Ryan M. Pitts, Medal of Honor recipient
- Maynard James Keenan lead singer of American rock band “Tool”
- Craig Morgan, country music singer
- Warren L. Ryland, 2/36th Infantry Bn - 2/3rd Field Artillery Bn, 3rd Armored Division, Germany 1975–1978, Inventor of FIST
- Christopher Mercer Lowe, Bronze Star w/ Valor, Collegiate Lacrosse Coach 
- Luke Thomas, MMA journalist
- Forward observers in Vietnam
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- (War Department Technical Manual TM 12-406)
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- Potter, E.B.; Nimitz, Chester W. (1960). Sea Power. Englewood Cliffs, New Jersey: Prentice-Hall. pp. 530–534.
- Potter, E.B.; Nimitz, Chester W. (1960). Sea Power. Englewood Cliffs, New Jersey: Prentice-Hall. pp. 630–634.
- Band of Brothers
- NAVMC 3500.42_ Tactical Air Control Party Training and Readiness Manual
- How to Become a Artillery Or Naval Gunfire Observer
- Close Air Support. United States Department of Defense, 2014
- "Joint Fires Observers make battlefield impact".
- Davis, Andrew. "Specialist Christopher "Kit" Lowe Receives Bronze Star". WSAV. Archived from the original on 1 November 2013. Retrieved 6 August 2018.
- U.S. Army FM 6-30
- U.S. Army FM 21-18 Procedures and Techniques of Foot Marches
- U.S. Army ATP 3-09.30