The Army Appropriation Bill created by an act of Congress on 2 March 1899 authorized the creation of the first body of native troops in Puerto Rico.

[8] Formed by four companies named A through D and assigned to San Juan, Mayagüez and Ponce, the unit was activated on 20 May 1899, led by Major Lorenzo Davinson.

[10] On 23 April 1904, Congress authorized the recruitment of the local population as second lieutenants, leading to the recognition of Jaime Nadal, Henry Rexach, Pedro Parra, Eduardo Iriarte, Teofilo Marxuach, Eugenio María de Hostos, Luis Emmanuelli and Pascual López.

[11] Marxuach fired a warning shot from a cannon located at the Santa Rosa battery of El Morro fort, in what is considered to be the first shot of World War I fired by the regular armed forces of the United States against a ship flying the colors of the Central Powers,[12] forcing the Odenwald to stop and to return to port where its supplies were confiscated.

The regiment embarked on the battleship USS Wyoming to St. Croix and St. Thomas, United States Virgin Islands, as part of a joint defensive exercise from 8 December 1939–7 January 1940.

[19] After American entry into World War II, the 65th Infantry remained in the vicinity of Fort Buchanan until it was transferred to Camp Tortuguero in November 1942.

[10] On 21 January 1944, the regiment arrived at New Orleans, Louisiana, and was sent less than two weeks later to Fort Eustis, near Newport News, Virginia in preparation for overseas deployment to North Africa.

The regiment remained at Fort Eustis until it departed the Hampton Roads Port of Embarkation on 26 March 1944, arriving in North Africa on 5 April 1944.

In an apparent effort to boost the unit's morale, its new commander, West Pointer Colonel George A. Ford, personally led a patrol towards the German lines on 4 January 1945.

"That was the name of the more peaceful of the two original Indian tribes that inhabited the island of Puerto Rico "Borinquen", and many of the men were direct descendants of that industrious race of people.

On 3 July 1952, the regiment defended the main line of resistance (MLR) for 47 days and saw action at Cognac, King and Queen with successful attacks on Chinese positions.

In October 1952, the regiment also saw action in the Chorwon Sector and on Iron Horse, Hill 391, whose lower part was called "Jackson Heights" in honor of Capt.

Among those who distinguished themselves in combat and who served in the conflict as a member of the 65th Infantry was a young first lieutenant of Mexican American descent whose name is Richard Edward Cavazos.

According to cultural historian Silvia Álvarez Curbelo, the government of Puerto Rico, caught in the middle of a potentially damaging affair that could jeopardize its political agenda, kept silent for nearly two months.

Secret negotiations between the U.S. and Puerto Rican governments took place and the Secretary of the Army Robert T. Stevens moved quickly to remit the sentences and grant clemency and pardons to all those involved.

[43] The report also found bias in the prosecution of the Puerto Ricans, citing instances of Continental soldiers who were not charged after refusing to fight in similar circumstances, before and after Jackson Heights.

Master Sergeant Negrón distinguished himself by extraordinary heroism in action against enemy aggressor forces in the vicinity of Kalma-Eri, Korea, on 28 April 1951.

On that date, Sergeant Negrón took up the most vulnerable position on his company's exposed right flank after an enemy force had overrun a section of the line.

When notified that elements of the company were withdrawing, Sergeant Negrón refused to leave his exposed position, but delivered withering fire at hostile troops who had broken through a road block.

When the hostile troops approached his position, Sergeant Negrón accurately hurled hand grenades at short range, halting their attack.

The extraordinary heroism exhibited by Sergeant Negrón on this occasion reflects great credit on himself and is in keeping with the finest traditions of the military service.

According to the TAGOKOR Korean War Casualty File and the American Battle Commission site the members of the 65th who fought in Korea were awarded a total of 2,771 Purple Heart Medals.

[49][50] On 12 February 1951, General Douglas MacArthur, wrote in Tokyo:The Puerto Ricans forming the ranks of the gallant 65th Infantry give daily proof on the battlefields of Korea of their courage, determination and resolute will to victory, their invincible loyalty to the United States and their fervent devotion to those immutable principles of human relations which the Americans of the Continent and of Puerto Rico have in common.

On 21 February 1960, commemorated as National Guard Day, the 65th Infantry Regiment was formally transferred from the Regular Army to the PRNG, in an activity where Gen. Cesár Cordero handed the units colors to Col. Rafael Rodríguez.

The names of those killed in combat are inscribed in "El Monumento de la Recordación" (Monument of Remembrance), which was unveiled on 19 May 1996 and is situated in front of the Capitol Building in San Juan, Puerto Rico.

[57] On 7 June 2007, PBS aired The Borinqueneers, a documentary about the 65th Infantry written and directed by Noemí Figueroa Soulet with Raquel Ortiz as co-director.

In 2014 the National Puerto Rican Day Parade, which is attended by nearly two million people and broadcast live on Fox TV, was dedicated to the Borinqueneers.

On 13 December 2019, US President Donald Trump signed into law the H.R.2325 legislation to designate the facility of the United States Postal Service located at 100 Calle Alondra in Río Piedras, Puerto Rico, as the "65th Infantry Regiment Post Office Building".

"[64] While a civilian award, generally recognizing single individuals (politicians, scientists, actors, military leaders, civilian heroes and others) or small groups (people who took a stand for civil rights and others), Congressional Gold Medals have also been awarded to a few military units, such as the Native American code talkers,[65] and the Japanese American 100th Infantry Battalion and 442nd Infantry Regiment,[66] the Tuskegee Airmen,[67] and others.

The 65th Infantry Borinqueneers Congressional Gold Medal has, for the obverse, a design depicting a close-up portrait of a unit staff sergeant, with three soldiers traversing rocky ground in the background.