MCL helped to lead the effort to form the Marin County Open Space District, now called Marin County Parks, with planning and publicity for the eventual successful election.

MCL continues to work on preserving important natural features of Marin. Projects have included the San Rafael Shoreline, Corte Madera marshes, Bahia, Rush Creek in Novato, Bel Marin Keys and other creeks, wetlands and ridges.