NEW YORK. — AS HUMAN BEINGS rarely live past 100, centennials are special anniversaries. They note the movement of events from the contemporary to the historical, from the ''real'' to the semimythical. This year the United States marked the 100th anniversary of the closing of its western frontier. By 1890, three centuries of westward conquest and settlement had washed across the continent, putting an end to America's brawling, bloody, teen-age years.
The census report of 1890 notes our coming of age in dry, bureaucratic prose:
''Up to and including 1880 the country had a frontier of settlement, but at present the unsettled area has been so broken into by isolated bodies of settlement that there can hardly be said to be a frontier line . . .''
December 29, 1890: In Washington, the Great White Father is Benjamin Harrison. On the Great Plains, the Ghost Dance religion is sweeping the defeated tribes, promising the return of the buffalo and the end of the white man. Hate, hunger and despair simmer on the reservations, and war is in the air.
On the snow-blown plains of South Dakota, on the Pine Ridge Indian Reservation, Miniconjou Sioux under Big Foot are gathered along a creek called Wounded Knee. The Seventh Cavalry, Custer's old regiment, has been sent to disarm them and has taken up positions surrounding the encampment. Women and children are with the band, and the Sioux are reluctant to give up their arms. Anger in the camp is high over Sitting Bull's death at the hands of reservation police a week earlier. Some warriors dance the hypnotic, grueling rituals central to the Ghost Dance and prepare for battle. Some historians think the Seventh Cavalry is looking for a fight, eager to avenge its defeat at Little Bighorn 14 years earlier.
Whoever begins it, the fighting is fierce and desperate. Many warriors are convinced that their special ''ghost'' shirts will protect them from the soldiers' bullets and charge headlong at the encircling wall of blue. There is bloody, hand-to-hand fighting, and the Sioux breach the soldiers' lines, only to be cut down by the army's new, rapid-fire Hotchkiss guns. At least 146 Sioux die, including 62 women and children. Twenty-five soldiers are killed. More on both sides die in the battle's aftermath, and troop strength on the reservation eventually swells to 3,500. It is a definitive show of strength, and Indian resistance dies quickly.
More than the battle against the elements, beasts and the unknown, the Indian wars defined the frontier in the popular imagination. As the last battle between red man and white recorded in official U.S. military history, Wounded Knee marked the final defeat of the continent's indigenous people at the hands of the invaders from Europe and has become the most powerful symbol of frontier's end.
Astonishingly, it happened such a short time ago. Into the 1950s and '60s, even '70s, participants and observers of the battle were still living. Today only a Methuselah or two among the Sioux, children at the time, may recall the hurtling of brave warriors, the crack of rifle fire in the frozen air and the screams of the dying. Soon they too will be gone.
And so this year we commemorate not only the end of the Indian way of life and the passing of the Great West, but the passage of those times beyond the horizon of first-hand memory and into the maw of the all-consuming past.
Peter Kelegian is a writer living in New York City.