The 1964 Wilderness Act instantly protected 9.1 million acres of wilderness. Since then, the wilderness system has grown to over 106 million acres. Much of that came in the late ’70s and mid-’80s, as wilderness areas identified by the Forest Service’s two Roadless Area Review and Evaluation programs were formally protected. (And 55 million acres of Alaska wilderness were added in 1980, more than doubling the size of the wilderness system.) A slew of BLM wilderness bills passed in the late ’80s and early ’90s, but 1994 — the year of the "Gingrich Revolution" — was the last big year for wilderness protection (Source: Doug Scott, Campaign for America’s Wilderness).