Long range recon patrol or LRRP (pronounced "lurp"), is a term used by the US army for small reconnaissance units working behind enemy lines for extended periods of time. LRRPs are typically used to
reconnoiter the landscape to ensure accurate maps, scout enemy troop strength and location, or cache supplies for future use. Then they have to sneak back out without getting caught. Theoretically, LRRPs are not supposed to make contact with the enemy, but there are very few "supposed to's" that last long in warfare.
The men chosen for these extremely dangerous assignments are a special breed of soldier. Known as "lurps" from the acronym LRRP, they have to be able to run several hundred miles over the span of a few days, navigate through trackless, unknown country, and subsist alone in the wilderness for days on end. All without being discovered by the enemy forces that are all around them. In other words, they have to be really sneaky bastards.
Longe range recon patrols were developed by the Army in the late 1950s for use against the communists in East Germany, based on similar units employed by the British in Southeast Asia in World War II. LRRPs were most famously employed against the Viet Cong in the Vietnam War. Typically, six-man teams would go on six-day missions behind Viet Cong lines and then be extracted by helicopters of the Air Cav. The best known LRRP units in Vietnam were the army rangers attached to the 1st Brigade of the 101st Airborne Division.