| National Wilderness | National Wild and | |
| Year | Preservation System | Scenic River System |
| million acres | river miles | |
| 1968 | 10.03 | 773 |
| 1969 | 10.19 | 773 |
| 1970 | 10.40 | 868 |
| 1971 | 10.40 | 868 |
| 1972 | 11.03 | 895 |
| 1973 | 11.03 | 961 |
| 1974 | 11.38 | 1,018 |
| 1975 | 12.72 | 1,145 |
| 1976 | 14.45 | 1,610 |
| 1977 | 14.49 | 1,610 |
| 1978 | 19.00 | 2,299 |
| 1979 | 19.00 | 2,299 |
| 1980 | 79.71 | 5,662 |
| 1981 | 79.84 | 6,908 |
| 1982 | 79.88 | 6,908 |
| 1983 | 80.21 | 6,908 |
| 1984 | 88.55 | 7,217 |
| 1985 | 88.70 | 7,224 |
| 1986 | 88.80 | 7,363 |
| 1987 | 88.99 | 7,709 |
| 1988 | 90.81 | 9,264 |
| 1989 | 91.46 | 9,281 |
| 1990 | 94.97 | 9,318 |
| 1991 | 95.03 | 9,463 |
| 1992 | 95.39 | 10,295 |
| 1993 | 95.44 | 10,516 |
| 1994 | 103.72 | 10,734 |
| 1995 | 103.60 | 10,734 |
| 1996 | 103.60 | 10,815 |
| 1997 | 103.60 | 10,815 |
| 1998 | 104.57 | 10,896 |
| 1999 | 104.75 | 10,931 |
Sources: Landres, P. and S. Meyers. A National Wilderness Preservation System Database: Key Attributes and Trends, 1964-1998. Gen. Tech. Rep. INT-GTR-18 (U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Ogden, UT, 1998).
U.S. Department of Agriculture, Forest Service, National Wilderness Preservation System Database (an Internet accessible database, as of April 15, 2000).
U.S. Department of the Interior, National Park Service, River Mileage Classifications for Components of the National Wild and Scenic River System (an Internet accessible data table, as of April 15, 2000).
Notes: Data reflect year-end cumulative totals.
Last Updated on