Arizona Highway 366 (Swift
Trail) provides access to within two miles of the Mt. Graham International
Observatory (MGIO). Landmarks and mile posts are located along Swift Trail
and are listed below:
| Location |
Milepost Marker |
Miles for Basecamp |
| MGIO Base Camp |
114.7 |
0.0 |
| Marijilda Canyon Road Intersection |
116.8 |
2.1 |
| 4,000' Elevation Marker |
117.5 |
2.8 |
| Coronado Forest Boundary |
118.5 |
3.8 |
| FR-861 Road Intersection (Heliport) |
119.5 |
4.8 |
| FR-667 Road Intersection – USFS Work
Site (5,000’ elevation) |
120.4 |
5.5 |
| Noon Creek crossing |
121.0 |
6.2 |
| FR-329 Road Intersection – Angle
Orchard |
121.4 |
6.4 |
| Round the Mountain Trailhead turnout |
121.5 |
6.5 |
| 6,000' Elevation Marker |
123.3 |
8.3 |
| Wet Canyon Bridge |
123.6 |
8.6 |
| Arcadia Campground |
125.5 |
10.4 |
| Cluff Dairy Turnout (Heliport) |
126.2 |
11.0 |
| 7,000' Elevation Marker |
126.6 |
11.4 |
| Turkey Flat (old general store) |
127.9 |
12.7 |
| Twilight Campground Road Intersection |
128.4 |
13.2 |
| 8,000' Elevation Marker |
130.1 |
14.9 |
| Lady Bug Saddle (8,508' Elevation) |
131.0 |
15.8 |
| Utility Corridor |
132.1 |
16.9 |
| Hagens Point (The Kitchen) |
133.3 |
17.9 |
| 9,000' Elevation Marker |
134.5 |
19.1 |
| Snow Flat Campground Road Intersection |
135.2 |
19.8 |
| Shannon Campground & Heliograph Peak
Road Intersection |
135.8 |
20.4 |
| FR-507 Intersection (High Peak) |
136.1 |
20.7 |
| Swift Trail (Hwy 366) Main Gate |
136.2 |
20.8 |
| Treasure Park Road Intersection |
137.0 |
21.6 |
| Hospital Flat Campground (Alternate
Heliport) |
137.2 |
21.8 |
| Grant Hill Intersection |
137.8 |
22.4 |
| Grant Creek crossing |
139.2 |
23.6 |
| Cunningham Campground |
139.9 |
24.3 |
| Moonshine Creek crossing |
140.6 |
25.0 |
| Post Creek crossing |
141.4 |
25.8 |
| Ft. Grant Vista Overlook |
141.8 |
26.2 |
| MGIO -
Emerald Peak Access Road Intersection |
142.3 |
26.7 |
| Old Columbine - Bible Camp Road
Intersection (Heliport) |
143.2 |
27.6 |
| Public Horse Corral |
143.3 |
27.7 |
| Soldier Creek Campground |
143.7 |
28.1 |
| Peters Flat |
144.3 |
29.0 |
| Chesley Flat |
145.5 |
30.2 |
| FR-287 Riggs Lake Road Intersection |
147.5 |
32.2 |
