The western terminus of NH 49 is in Campton at U.S. Route 3. Heading east over the Pemigewasset River, there is an interchange with I-93 (exit 28) shortly after the bridge. Turning northeast to follow the Mad River, NH 49 passes through the Lower and Upper Villages of Campton, intersecting with NH 175 before entering the town of Thornton. Passing the community of Goose Hollow, NH 49 enters the White Mountain National Forest as it crosses from the west to the east bank of the Mad River, and enters the town of Waterville Valley. Upon entering the Waterville Valley Resort, the state route ends, though signage is unclear exactly where. NH 49 is one of the few New Hampshire State Routes which does not end at another numbered route. The Waterville Valley portion of Rt. 49 is named for Army SPC Marc Decoteau, killed in Afghanistan on January 29, 2010.[2]
NH 49 is the only road into or out of Waterville Valley during the winter. In the summer months residents can also take Tripoli Road to the northwest.
