$15 for a Weekend Pass (Fri - Sun)
$10 for a Weekday Pass (Mon - Thur)
$30 for an Annual Pass which includes Mount Adams and Mount St. Helens.

Single trip passes are available at:

Mt. Adams Ranger Station
2455 Hwy 141
Trout Lake, WA 98650
(509) 395-3400

Cowlitz Valley Ranger Station
10024 US Hwy 12
PO Box 670
Randle, WA 98377
(360) 497-1100

or by Mail (pdf form, rtf Form)

Group size maximum, 12.
Blue Bags are required to be carried and are available at the Ranger Stations.