In 1990 a concerned group of citizens marched from Snoqualmie Pass to the Seattle waterfront to publicize the need to save some of the nearby forests and open spaces just outside of the growing city. From that group of activists, the nonprofit, 501(c)3, Mountains to Sound Greenway Trust was formed in 1991.

The Board of Directors and Advisory Council include major land owners and managers along Interstate 90, foresters, business representatives, recreation groups, environmentalists, community activists, elected leaders and government agencies.

The Greenway Trust also relies on a 70-member Technical Advisory Committee of citizens and experts along the corridor. This group developed the comprehensive Greenway Concept Plan that inspires landowners and government agencies to voluntarily carry out Greenway goals.The Greenway staff works on projects large and small throughout the 100-mile Greenway by:

• Supporting communities and public agencies in acquiring open space lands for permanent protection

• Planning for and helping communities link a regional Greenway Trail system

• Supporting historic preservation and interpretation projects
• Developing programs for environmental education
• Recruiting people of all ages for large-scale environmental restoration and stewardship of public open spaces
• Providing a forum where diverse public and private interests can work toward practical solutions to balance conservation with economic prosperity