The mission of Greenstone Adventures is to inspire youth through wilderness immersion. We want to share our passion for the outdoors and our country's most beautiful, wild places with as many youth as possible. We believe that through direct exposure to tangible, real-life challenges and navigable risk we can teach and inspire the next generation to think critically, problem solve, communicate cooperatively within a team, and be more confident and independent. These benefits combine to give our youth a deeper understanding and appreciation for our natural world, ultimately creating a more environmentally responsible society.



George Mackaronis 

George is the founder and co-owner of Greenstone Adventures, as well as a lead guide. He is from Mclean, Virginia where he grew up camping and exploring Great Falls Park and Catoctin Mountain Park with his family. He has been an avid backpacker and climber for over 10 years, and he has taught those skills in various guide and teaching positions since 2011.

George moved to Charlottesville, Virginia in 2012 and is currently in his fourth year teaching at Free Union Country School. George teaches pre-K through 5th grade Physical and Environmental Education at Free Union, and helps lead the Free Union nature and sports camps. He received a BA in psychology from Denison University in Granville, Ohio, and has held a Wilderness First Responder (WFR) certification since 2012. He is also a certified Virginia Master Naturalist and is the assistant coach of the boys' varsity lacrosse team at The Covenant School. In his spare time, George can be found running with his dog Jojo or woodworking in his basement. 


Andrew Eaton

Andrew is a lead guide and co-owner of Greenstone Adventures. He is from Chesapeake, Virginia and has been living and exploring in central Virginia for 8 years. Andrew has experience backpacking, climbing, and mountaineering in our country's most beautiful mountain ranges. He spent two seasons as a backpacking instructor and counselor for the historic Cheley Colorado Camps in Estes Park, Colorado, where he led high school age boys on 3 and 5 day backpacking trips into Rocky Mountain National Park and the Indian Peaks Wilderness Area. He also worked with the Cheley Fall Discovery Program as a guide for 8th graders.  He is eager to bring his experience to Virginia's youth.

Andrew attended the University of Mary Washington where he graduated with a BA in Political Science in 2007.  He is an avid reader, aspiring baker, and amateur philosopher.  Andrew volunteers locally as a Big Brother and can often be found running the Monticello trails with his dog, Franklin. 

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Sydney Halleman

Sydney is an assistant guide for Greenstone Adventures. Born and raised on the cusp of San Francisco, Sydney now attends the University of Virginia studying a pre-law track. She’s an avid skier, mountain biker, rock climber, and hiker. She gained backpacking experience in high school, exploring Shenandoah National Park and the mountains of nearby West Virginia. Since moving to Charlottesville, Sydney has become active with the UVA Outdoors Club, where she serves as executive Gear Master, responsible for all the club's expedition gear. She leads climbing, backpacking, and mountain biking trips for the 800 members of the school club. Sydney is also an employee of the University's Outdoor Recreation, where she leads night hikes for incoming university students, supervises the University bouldering wall, and works outdoors at Poplar Ridge, leading members of the community in team-building exercises in the secluded woods of Observatory Hill. Sydney's biggest adventures include mountain biking the Magnificent Seven trail in Moab, Utah, skiing fresh powder backcountry at Alta, Utah, and rock climbing in Jackson Hole. Sydney is trained in first-aid and CPR."

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Jimmy McDonnell 

Jimmy is an assistant guide for Greenstone Adventures. Born in South Carolina and a recent graduate of Tandem Friends School in Charlottesville, Jimmy will be continuing his education as a freshman at Longwood University's Nursing School this fall. Jimmy first got into backpacking when he helped lead a backpacking trip with Tandem Friends School during their emphasis week. He helped lead ten 5th-8th graders for 3 nights along the Appalachian Trail. Inspired by his experience, he signed up for a NOLS backpacking course last summer. During the course Jimmy hiked over 100 miles of the Wind River Mountain range of Wyoming over 30 days, learning how to pack efficiently, assess dangerous situations, and live safely in the backcountry. On the final week of his trip, Jimmy was chosen as the ISGE (independent student group expedition) leader, and created a 4 night, 25 mile plan in which he lead 5 other students to rendezvous with their instructors at a designated pick up zone. After doing such a great job as the ISGE leader, Jimmy was invited to take a NOLS Instructor course, which he will be completing during college. Jimmy is also certified in life guarding, basic first aid, and CPR/AED.