Jesus Gil Abreu (September 1, 1823 – June 30, 1900) was a rancher and pioneer who owned a New Mexico ranch that now comprises Philmont Scout Ranch.
He was born in Santa Fe, New Mexico. His father was on the staff of New Mexico Governor Albino Pérez and was killed along with the governor during the Revolt of 1837 (New Mexico).
After the revolt, he headed east on the Santa Fe Trail where he worked for Kansas City, Missouri founder John Calvin McCoy at Westport, Kansas City and Independence, Missouri.
During the Mexican-American War in 1845 he was engaged by a sutler to be an interpretor for the United States Army. When the troops were dispatched to Santa Fe Ceran St. Vrain dispatched Abreu in advance to buy up the goods of competing sutlers for St. Vrain so it could enjoy a monopoly with the United States.
Abreu worked in a store for St. Vrain in Santa Fe, and worked as an interpretor for the United States and in the winter of 1848-49 delivered the U.S. mail between Santa Fe and Fort Leavenworth, Kansas (a process which took 40 days).
During the California Gold Rush he traveled to California in 1850-51.
When he returned to New Mexico he worked for Joseph Pley, a partner of Lucien B. Maxwell who after marrying the daughter of Carlos Beaubien had become the owner of the million-acre Maxwell Land Grant.
He at first worked in Mora, New Mexico and then at the Maxwell store in Rayado.
On November 26, 1859, he married Petrita Beaubien, another daughter of Beaubien. In 1862 he acquired 20,000 acres (81 km2) of the land grant for his Abreu Ranch.
A history of the New Mexico described the ranch:
The family sold most of the ranch in 1911 after his death and was bought by Waite Phillips in the 1920s who was to donate 35,857 acres (145.11 km2) to the Boy Scouts of America in 1938.