Few sights in the world rival northwestern Arizona’s Grand Canyon of the Colorado River, which lies just south of Utah and east of Nevada. The colorful, eroded gash in the Earth’s crust is 277 miles long and an average of 10 miles wide. At its deepest, it plunges 6,000 feet from rim to river. So deep is the sheerwalled canyon, where the rock strata reveal 250 million to 2 billion years of the Earth’s history, that getting to the bottom and back (on foot or by mule) takes two days. A trip through the canyon by river raft can take two weeks, and experienced backpackers can spend weeks in the more remote areas of the canyon.

The park’s elevation and climatic variations encompass multiple life zones, from the canyon-bottom desert of cacti and creosote bush to woodlands of pinyon pines and junipers and, at the higher elevations, conifer forests.As geologic forces lifted the Earth’s crust to form the high Colorado Plateau, the Colorado River slowly eroded its way downward through thousands of feet of rock. Split-twig figurines found in caves have dated human habitation to at least 2000 BC.

Havasu Canyon, a tributary of the Grand Canyon, is part of the Havasupai Indian Reservation.The first recorded view of the canyon was by a member of the 1540-42 expedition of Spanish explorer Francisco Vasquez de Coronado. In 1869, Major John Wesley Powell’s expedition down the Colorado River was the first to explore the canyon’s full length.

Today, an average of 5 million visitors annually keep the park crowded most of the year, making advance planning and reservations for campsites, lodging, mule trips, and backcountry permits essential. Visitor numbers are heaviest in spring, summer, and fall, and lowest from November through February, when winter conditions prevail. Day visitors are encouraged to arrive early due to limited parking.

The South Rim, more than 7,000 feet above sea level, is open year-round, 24 hours a day. Winter can bring snow, and even summer nights are cool. In the canyon, however, summertime temperatures can reach 120 F. The North Rim, at 8,000 feet, can receive snow almost any time of year, and heavy snow closes roads in winter; the weather is changeable in spring and fall. The North Rim is open from mid-May to mid-October.

There is a park entrance permit per vehicle which is good for seven days. There are information centers at both the South Rim and North Rim.

Commercial flights are available from Las Vegas, as well as from Phoenix, Flagstaff, and Grand Canyon Airport in Tusayan, south of the park. The South Rim’s Grand Canyon Village is 60 miles north of I-40 via State Route 64/US-180, and 80 miles northwest of Flagstaff via US-180.A variety of lodging choices and campground facilities are available for overnight stays.