A Life Shaped by Purpose, Policy, and the Land

These days, life moves at a different pace for Mary Shallenberger ’66. Happily retired, now calls a ranch in California’s Central Valley home, describing it as her own piece of paradise. Where her early years were filled with hunter and jumper riding, a passion she first nurtured at Chatham Hall, she has since traded that discipline for riding, working with, and breeding quarter horses. With a few beloved brood mares, beef cows grazing the land, and two loyal Labradors always at her side, each day is grounded in the rhythms of the land and the joy of caring for animals, especially welcoming new foals into the world.

Her journey since Chatham Hall has been anything but ordinary. After graduating, she spent a year in Edinburgh, Scotland, attending St. George’s School for Girls as an exchange student through the English Speaking Union. The experience broadened her worldview and set the stage for her next chapter at Mount Holyoke College, where she earned a Bachelor of Science in Biology.

Following graduation, a spontaneous decision led her to drive across the country to California, simply because it felt like an adventure worth taking. “After graduation, I drove across the country to California, just because it seemed like a fun idea, which it was,” she shares. That leap landed her in a biology lab at Stanford University. While the work was meaningful, it ultimately clarified where her true passion lay: protecting the environment and stewarding natural resources. With that realization, she returned to Stanford to earn a Master of Science in Civil Engineering, not with the goal of becoming an engineer, but as a strategic step toward influencing environmental public policy.

That decision proved transformative. For the next four decades, she served in the California state government, working in the Governor’s Office on policy research, at the Air Resources Board on air quality planning, and in the State Senate, both for committees and ultimately for the President of the Senate. Her career culminated with an appointment to the California Coastal Commission, where she served for nearly 15 years, helping protect one of the state’s most vital and treasured natural resources until her retirement from public service.

Alongside her professional work, she dedicated herself deeply to women’s rights and health care, serving on several boards and eventually becoming the Chair of one such organization. She also served as President of the Guttmacher Institute Board, supporting research and policy work focused on sexual and reproductive health and rights. Through volunteer roles, these positions were as demanding and rewarding as her work in government, reflecting a lifelong commitment to advocacy, equity, and access.

When asked what she is most proud of, she resists narrowing it to a single accomplishment. Protecting coastlines, preserving habitats, and expanding access to health care for women are ongoing efforts, she notes, requiring constant vigilance and care. The work is never finished, and that truth continues to guide her even in retirement.

At the heart of it all is Chatham Hall. She reflects on her time at Chatham Hall fondly. “My years at Chatham Hall were the most formative years of my life. Chatham set the compass for the rest of my life. I learned to be kind and to be respectful of others, sometimes to be humble, and always to strive for joy. I learned how to study and that learning should be a creative experience. I graduated from Chatham Hall as a confident young woman.”

Her story is a powerful reminder that lives of impact are often built through curiosity, courage, and a willingness to follow purpose wherever it leads, from classrooms to coastlines, from policy chambers to open fields, and always guided by the values first shaped at Chatham Hall.