Monadnock Paper Mills Joins Sustainable Green Printing Partnership Membership Highlights Environmental Leadership and Commitment to Sustainable Supply Chain Login or register now to gain instant access to the rest of this premium content! Monadnock Paper Mills, Inc., the oldest continuously operating paper mill in the United States, has joined as a patron of the Sustainable Green Printing Partnership, highlighting its environmental leadership and commitment to the industry’s growing sustainable supply chain. The Sustainable Green Printing Partnership (SGP) is a non-profit organization that certifies printing facilities’ sustainability best practices, including and beyond regulatory compliance. SGP advocates best practices and innovation among print community stakeholders, aligning the printing industry and its customers in the pursuit of a more accountable sustainable supply chain.