The National Trail is the backbone of South Mountain Park and Preserve, one of the largest municipal parks in the United States at roughly 16,000 acres on the southern edge of Phoenix. Running about 14 to 15 miles across the entire range from east to west, it rides the crest of the mountains and links up with most of the park's other trails, making it the classic long traverse of this vast desert playground on the city's doorstep.

From the Pima Canyon trailhead on the east side, hikers pick up the National Trail and follow it as it skirts the ridges past a string of landmarks: Hidden Valley, with its natural rock tunnel and the squeeze of Fat Man's Pass; the Buena Vista Lookout; the curious dry-stacked Chinese Wall; Telegraph Pass; and Goat Hill, before the long descent to the San Juan Lookout at the west end. Along the way are ancient Hohokam petroglyphs, abandoned mine workings and interesting rock formations, with sweeping views over the Phoenix valley the whole distance.

It is a rugged, rocky trail with steady ups and downs rather than one big climb, and most of the foot and bike traffic stays on the more accessible eastern half. This is exposed Sonoran Desert with essentially no water and little shade, so it is a cool-season route: summer heat here is dangerous and regularly deadly for the unprepared, making fall through spring the season and an early start essential. For hikers, trail runners and mountain bikers, the National Trail is the ultimate way to experience the wild heart of South Mountain.