Union Square is a 2.6-acre public plaza bordered by Geary, Powell, Post, and Stockton Streets in downtown San Francisco, California. "Union Square" also refers to the central shopping, hotel, and theater district that surrounds the plaza for several blocks. The area got its name because it was once used for Thomas Starr King rallies and support for the Union Army during the American Civil War, earning its designation as a California Historical Landmark.