This trail provides access to the upper slopes of Mt. Hopkins, the second most prominent peak in the Santa Ritas. The Agua Caliente Trail winds along Hopkin's north slopes through a cool forest of conifers, oaks, and aspens, providing good views of the Fred Lawrence Whipple Observatory on the mountain's summit as well as the upper reaches of Madera Canyon and Mt. Wrightson's rocky prominence across the canyon. Off in the distance, the Santa Cruz Valley (to the west), the Santa Catalina Mountains (to the north), and the Rincon Mountains (to the northeast) stretch toward the horizon.

Agua Caliente's trailhead is located in a canyon of the same name on Mt. Hopkin's western flank. From that point, accessible via the Mt. Hopkins Road, the trail proceeds up a remote desert canyon toward the mountain's forested upper slopes. If you arrange a shuttle in advance, a trip that stretches between this trailhead and the Very Steep/Vault Mine trailhead in Madera Canyon makes a good long day hike. A loop that doesn't require a shuttle takes you up the Very Steep/Vault Mine trail to Agua Caliente Saddle, then northeast to Josephine Saddle and back to the Roundup parking Area via the Lower end of either Old Baldy or Super Trail.

4.7 miles of the Agua Caliente Trail are within the Mt. Wrightson Wilderness. Mechanized vehicles, including mountain bikes, are not permitted in Wilderness areas.

Directions: From Tucson, Leave Interstate 19 at the Canoa Road Exit. Take the east frontage road, 3 miles south to Elephant Head Road and turn east 1.6 miles to the Mt. Hopkins Road. Drive 4.5 miles to Forest Road 183, turn north on this dirt road about 2.4 miles to the trailhead at the canyon.

The Agua Caliente Trail winds along Hopkin's north slopes through a cool forest of conifers, oaks, and aspens, providing good views of the upper reaches of Madera Canyon.