Greg King (born 1961) is an American journalist and environmental activist in Northern California. He is President and Executive Director of Siskiyou Land Conservancy, a non-profit land trust. King is credited with discovering and naming Headwaters Forest, in March, 1987, then the largest privately held ancient redwood grove still standing outside of parks. As a redwood activist King pioneered the tactic of tree-sitting, and he was a lead organizer and strategist dedicated to protecting Headwaters and other groves during the 1980s and 1990s. King is an authority on redwood logging and protection efforts that have occurred since 1850.