Answer by taking a quote from the following article:

Sources differ on the precise year of Crazy Horse's birth, but most agree he was born between 1840 and 1845. According to a close friend, he and Crazy Horse "were both born in the same year at the same season of the year," which census records and other interviews place in 1842. Encouraging Bear, an Oglala medicine man and spiritual adviser to the Oglala war leader, reported that Crazy Horse was born "in the year in which the band to which he belonged, the Oglala, stole One Hundred Horses, and in the fall of the year," a reference to the annual Lakota calendar or winter count. Among the Oglala winter counts, the stealing of 100 horses is noted by Cloud Shield, and possibly by American Horse and Red Horse owner, as equivalent to the year 1840-41.

Crazy Horse is commemorated by the incomplete Crazy Horse Memorial in the Black Hills of South Dakota, near the town of Berne. Like the nearby Mount Rushmore National Memorial, it is a monument carved out of a mountainside. The sculpture was begun by Polish-American sculptor Korczak Ziolkowski, who had worked under Gutzon Borglum on Mount Rushmore, in 1948. Plans call for the completed monument to be 641 feet (195 m) wide and 563 feet (172 m) high. Ziolkowski was inspired to create the Crazy Horse Memorial after receiving a letter from native Lakota chief Henry Standing Bear, who asked if Ziolkowski would be interested in creating a monument for the native North Americans to show that the Indian nations also have their heroes. The Native Americans consider Thunderhead Mountain, where the monument is being carved, to be sacred ground. Thunderhead Mountain is situated between Custer and Hill City. Upon completion, the head of Crazy Horse will be the world's largest sculpture of the human head, measuring approximately 87 feet (27 m) tall, more than 27 feet taller than the 60-foot faces of the U.S. Presidents depicted on Mount Rushmore, and the Crazy Horse Memorial as a whole will be the largest sculpture in the world. The memorial is funded entirely by private donations, with no assistance from the U.S. federal government. There is no target completion date at this time; however, in 1998, the face of Crazy Horse was completed and dedicated. The Crazy Horse Memorial Foundation regularly takes the lead in cultural, social and educational events, including the Volksmarch, the occasion on which the public is allowed into the actual monument grounds. The foundation generates most of its funds from visitor fees, with visitors numbering more than one million annually. The monument has been the subject of controversy. In Ziolkowski's vision, the sculpted likeness of Crazy Horse is dedicated to the spirit of Crazy Horse and all Native Americans. It is well-known that Crazy Horse did not want to be photographed during his lifetime and is reportedly buried in an undisclosed location. While Lakota chief Henry Standing Bear believed in the sincerity of the motives, many Native Americans still oppose the intended meaning of the memorial. Opponents of the monument have likened it to pollution and desecration of the landscape and environment of the Black Hills, and of the ideals of Crazy Horse himself. Aside from the monumental sculpture, Crazy Horse has also been honored by having two highways named after him, both called the Crazy Horse Memorial Highway. In South Dakota, the designation has been applied to a portion of US 16/US 385 between Custer and Hill City, which passes by the Crazy Horse Memorial. In November 2010, Nebraska Governor Dave Heineman approved designating US 20 from Hay Springs to Fort Robinson in honor of Crazy Horse, capping a year-long effort by citizens of Chadron. The designation may extend east another 100 miles through Cherry County to Valentine.

Where is it located?
in the Black Hills of South Dakota, near the town of Berne.