Henry Glass was a rear admiral in the United States Navy, best remembered for his role in the bloodless capture of Guam in the Spanish–American War. He was also a Union veteran of the American Civil War.

The Capture of Guam was a bloodless engagement between the United States and Spain during the Spanish–American War. The U.S. Navy sent a single cruiser, USS Charleston, to capture the island of Guam, which was under Spanish control. However, the Spanish garrison on the island had no knowledge of the war and no real ability to resist the American forces. They surrendered without resistance, and the island passed into American control. The event was the only conflict of the Spanish–American War on Guam.