| Sinclair Mountain | |
| Elevation: | 6800feet |
| Elevation Ref: | [1] |
| Prominence Ft: | 3600 |
| Isolation Mi: | 10.95 |
| Range: | Coast Mountains Boundary Ranges |
| Location: | Tongass National Forest Haines Borough Alaska, United States |
| Map: | USA Alaska |
| Label Position: | left |
| Coordinates: | 59.0967°N -135.1239°W |
| Topo: | USGS Skagway A-1 |
| Rock: | granite |
| First Ascent: | 1973 |
| Easiest Route: | [2] |
Sinclair Mountain is a prominent 6800feet mountain summit located in the Boundary Ranges of the Coast Mountains, in the U.S. state of Alaska. The peak is situated 260NaN0 south of Skagway, and 150NaN0 north of Lions Head Mountain, on land managed by Tongass National Forest. Although modest in elevation, relief is significant since Sinclair Mountain rises 6,800 feet above the entrance to Chilkoot Inlet in 3.50NaN0. The peak's name was established in 1920 by the United States Coast and Geodetic Survey to remember Cephas Hempstone Sinclair (1847–1920), hydrographic and geodetic engineer who had 47 years of field service with that agency.[3] The mountain's toponym was officially adopted in 1920 by the U.S. Board on Geographic Names.[4] The first ascent of this seldom climbed peak was made in mid-June 1973 by Jerry Buckley, Joe Greenough, and Craig Lingle.[5] [6]
Based on the Köppen climate classification, Sinclair Mountain has a subarctic climate with cold, snowy winters, and cool summers.[7] Weather systems coming off the Gulf of Alaska are forced upwards by the Coast Mountains (orographic lift), causing heavy precipitation in the form of rainfall and snowfall. Temperatures can drop below −20 °C with wind chill factors below −30 °C. This climate supports glaciers on the north, south, and east sides of this mountain. The months May through July offer the most favorable weather for viewing or climbing Sinclair Mountain.