Wikipedia tells us that Lassen Peak is "the southernmost active volcano in the Cascade Range. Located in the Shasta Cascade region of Northern California, Lassen rises 3,500 ft (1,100 m) above the surrounding terrain and has a volume of 2 km3, making it one of the largest lava domes on Earth". Reason enough to visit this peak...

There's just one mountain in Northern California. At least one big mountain. The huge volcanic cone of Mt. Shasta can be seen from almost every place between Sacramento and the border to Oregon. Since the Mountain's base is at a mere 1000 m (~3000 ft) any climb on Mt. Shasta is strenuous with a huge height gain. The regular route...