The boundary of the Highlands region has been expanding over the years in response to state involvement and Congressional directives. Most recently, the Connecticut and Pennsylvania Highlands were added to the New York and New Jersey Highlands, with the passage of the Federal Highlands Conservation Act of 2004 (P.L. 108-42, United States Statutes at Large). The resulting Highlands boundary now encompasses 3.4 million acres, 25 counties, and 319 municipalities (Figure 1). The four-state Highlands region contains a wealth of natural resources and associated benefits: forests of oak, hickory, ash, pine, and hemlock; a rugged landscape of discontinuous, steep-sided ridges and plateaus; streams and lakes that provide drinking water for millions; forests that provide timber and game, and shelter hundreds of rare and beautiful plants and animals; and open spaces that offer diverse recreational opportunities. Development threatens to erase, fragment, and degrade forests, streams, and plant and animal communities in the Highlands. Also threatened are the benefits that these natural resources provide for residents of the Highlands and the vast metropolitan area to the east, such as clean drinking water and unfragmented forests.