Three attributes make Mark C. Pennington LLC distinctive: experience, focus, and style of work.


In over 35 years of practice, Mr. Pennington has helped clients through virtually all stages of the business life cycle. Over this time, he has built solid relationships with regulatory agencies, and with trusted professionals in related fields to whom he can turn to assist clients with their specific needs. He has managed complex situations, like spill response and cleanup in the middle of ongoing construction and litigation. He knows how to build a record and to manage communications cautiously and effectively.


For over twenty years in his prior firms, Mr. Pennington provided full-spectrum environmental counseling to a wide variety of clients in regulatory, transactional, and litigation matters. Since forming his own firm, he has continued to advise clients on a wide range of issues, but he puts special emphasis on helping clients with two complementary missions: (1) bringing contaminated urban properties back to productive use, and (2) conserving lands with ecological, scenic, and agricultural value. This focus and experience positions him well to provide high quality service to clients in assessing risk, crafting protective legal documents, maintaining compliance, supporting stewardship and enforcement activities, and resolving conflict. With John E. Osborn P.C. he delivers a unique blend of skill and experience in handling environmental problems that affect construction, both in the early planning stages and mid-project, when surprises can lead to delays and complications. In the urban environment, remediation and construction frequently go hand in hand. Projects with known environmental impacts often involve a remedial work plan of which an engineered structure is a key component. Successfully managing the interface between construction and remediation is a key element of project success. Too often, clients rely on firms for conventional construction contracts that do not adequately anticipate their needs, or on familiar contractors who may lack the necessary qualifications. When problems arise, it can be a logistical nightmare to coordinate a prompt and effective response. Our environmental and construction teams have deep experience with contaminated sites, and they work together seamlessly to plan projects and to get troubled projects back on track.

In conservation matters, Mr. Pennington draws on over 15 years of learning from regular participation in events sponsored by the Land Trust Alliance, on participation as a speaker in events sponsored by the New York State Bar Association, and on the substantial real estate experience of his colleague Eric Haas at John E. Osborn P.C., with whom he works closely on conservation transactions.

Work Style

We view our clients as business partners. We work to develop a deep understanding of their businesses and objectives. We strive to be responsive, prompt, and sensitive to the pressures they face. We communicate options and recommendations clearly. We are accessible, closely involved professionals—not detached managers of junior staff. We are equally as comfortable working with private sector clients as we are with the officers and boards of non-profits. We can provide full-project services, assisting with defining project scope, assembling the team, preparing the contracts, and overseeing performance. Or we can plug into an existing team to provide strategic advice on an as-needed basis. We are collaborative team players. When conflict arises, we work to articulate positions clearly and forcefully. We strive to manage litigation cost effectively. We work hard to earn and keep your trust.

Please call us at (914) 478-1258.