1. The Battle of Pecos River occurred on September 21, 1854, between the Jicarilla Apache and United States Army troops led by Captain Edmund B. Alexander. It resulted in a U.S. victory and set the stage for further conflict with Native American tribes.

2. On September 21, 1937, a record-breaking flood hit the town of Santa Clara Pueblo, causing significant damage to homes and infrastructure. The event spurred a push for flood control measures in the region.

3. The New Mexico State Fair, which dates back to 1889, typically begins on or around September 21 each year. The fair features livestock shows, carnival rides, concerts, and other forms of entertainment.

4. September 21, 1961, marked the day when the Mescalero Apache Tribe gained federal recognition from the United States government. The tribe now consists of over 4,000 members and operates a casino and other businesses.

5. In 2010, the University of New Mexico Health Sciences Center announced that it had received a $25 million grant from the National Institutes of Health to establish a Clinical and Translational Science Center. The center's mission is to accelerate the process of turning scientific discoveries into treatments and cures for patients. The grant was awarded on September 21 of that year.