Climbers come from all over the world come to tackle Shasta’s majestic 14,162-foot peak. Be sure to pack your sturdiest hiking boots and your strongest leg muscles; less than one-third of the 15,000 intrepid mountaineers who try to conquer Mount Shasta (www.climbingmtshasta.org) each year actually make it to the top.

If you’re serious, you’ll get plenty of help from the locals. Mountaineering and glacier classes are available, and several guides and outfitters can provide equipment and even lead you up the mountain. Take that help! You’ll be required to negotiate Shasta’s year-round icy glaciers, steep and rocky slopes, and extreme altitudes that thin the air to make the climb just that much tougher.

So what’s the good news? There are more than a dozen routes you can take to ascend to the top. You can pick a quick, hardcore climb that takes you from the base camp up to the top in a single day, or choose a longer and more leisurely trail and spend two days making the trek, camping overnight in the ultimate California wilderness.

The most popular route runs along Avalanche Gulch, and for the healthy and hearty, this can be the adventure of a lifetime. You’ll see Mount Shasta up close in ways that most casual tourists could never even imagine. The peak climbing season is June through August.

If you are a casual tourist, exercise care accessing even the trailheads that lead to Shasta’s peak. Some of the dirt roads around the base of the mountain require a four-wheel drive, and the weather conditions can severely impact the roads. To make this climb safely and successfully, you must be prepared, so check the web, talk to locals, and gather maps and equipment.

Nearby, the formation at Castle Crags State Park (on I-5, 6 miles south of Dunsmuir, 530/235-2684, www.parks.ca.gov) offers more than 40 established climbing routes, plus plenty of wide, open formations for explorers who prefer to climb where no one has climbed before. You’ll get to tackle domes, spires, and walls of granite that reach 6,000 feet up toward the sky.

The crags first thrusted upward, then broke off and were scrubbed by glaciers into the fascinating, climbable formations visible today. Some of the known favorite climbs at Castle Crags are the Cosmic Wall, Castle Dome East, and Six Toe Crack.