 Greenbelt Alliance expanded outside San Francisco with a field office in the South Bay in 1988.In 1995, East Bay and Sonoma-Marin field offices opened their doors, and in 2001, a Solano-Napa office opened in response to growth along the Interstate 80 corridor between San Francisco and Sacramento.In the 1990s and 2000s, Greenbelt Alliance was involved in stopping sprawl development proposals and protecting Pleasanton Ridge (1993), Bear Creek Redwoods(1999), and Cowell Ranch/John Marsh SHP (2002) as state parks or open space preserves.