North Table Mountain and South Table Mountain are two prominent basaltic plateaus overlooking the city of Oroville, California. They are named for their flat surface, like a table top; because of this it is often mistakenly called Table Top Mountain.
Both of the Table Mountains are the remainder of an ancient volcano flow, and ancient lava fields can still be found all over the mountain. Part of the Lovejoy Formation, the mountains are believed by some to date back to 14 million and 39 million years ago.
South Table Mountain, at 39°33′23″N 121°33′00″W / 39.55639°N 121.55000°W, is mostly privately owned, and contains the "O", which is a big "O" on the side of the plateau, that stands for "Oroville", the city that it towers over. Dedicated on June 8, 1929 by Oroville High School (OHS) alumni Morrow Steadman, the "big O" has a concrete thickness of four inches, and was measured by its builders to be 87 feet by 33 feet. It was intended to last through the generations and convey a spirit of good sportsmanship in local high school athletic events. The "O", and most of its access routes, are located on private property. It was to have another meaning, too, Steadman wrote in the '29 OHS Yearbook the Alpha, saying he hoped the "O" would remind students of "cooperation and teamwork, both on the athletic fields and in our school activities".
North Table Mountain, at 39°38′10″N 121°33′00″W / 39.63611°N 121.55000°W, is mostly private, but includes a small portion which is a wildlife area, and contains several vernal pools and waterfalls, including Phantom Falls, and Beatson Falls. There are no trails, so people who want to hike to the waterfalls have to find their own way. The best time to view the waterfalls is winter to early spring. They are usually dry during the summer months. Everything east of Cherokee Road in Morris Ravine is on private property and is off limits to visitors unless given specific permission.