Adirondack Trail Improvement Society (ATIS) | 45 followers on LinkedIn. The mission of ATIS is to inspire responsible ​stewardship and facilitate healthy enjoyment of wild lands and to support individuals in developing the skills and qualities necessary to thrive in the natural world and beyond. The mission is accomplished via educational and recreational programs for youth and adults from diverse communities and the maintenance and enhancement of public hiking trails in the ​vicinity of Keene Valley, New York.