Your Team

Estate Preservation & Planning  helps individuals, families, and business owners in Massachusetts and New Hampshire avoid unnecessary taxes, legal entanglements, and asset loss while preserving the security and freedom you have worked so hard to achieve.

Donald H. Sienkiewicz, Esq.

Attorney Sienkiewicz is the owner of Estate Preservation and Planning Law Office in Amherst and a partner in the Runyon Law Office in Peterborough. He practiced previously with Rath, Young, & Pignatelli in Concord New Hampshire and Goodwin Procter in Boston. He is admitted to the Bar in Massachusetts and New Hampshire.

Donald earned his Juris Doctor degree in 2002 from Northeastern University School of Law in Boston, Massachusetts. He also has a B.A. in Economics and a B.A. in Environmental Policy from Boston University. Before attending law school, he taught high school in Massachusetts, and spent four years leading wilderness expeditions for troubled teenagers in Utah, Arizona, Oregon, and California.

Donald enjoys skiing, hiking, and fishing, and lives with his wife, Katja and their four children in the beautiful Monadnock region of southern New Hampshire. Read more about Donald’s affiliations, experience and honors here.


Katja Sienkiewicz

Katja joined the firm in 2016 as the Outreach Coordinator.  Her background is in design/build and she has a M.A. in English Literature from Northeastern University in Boston, Massachusetts and a B.A. in English and a B.A. in Art History from Pine Manor College in Brookline, Massachusetts.
Katja enjoys carpentry, boat building, graphic design, photography and cheering on her kids on and off the field. She lives with her husband Donald and their four children in the beautiful Monadnock region of southern New Hampshire.


Sheryl E. Allen

Sheryl, our Document & Funding Coordinator, joined the firm in 2018.  She earned a B.A. in International Studies from the Metropolitan State College of Denver, and has worked in a wide array of business environments, including at McKinsey & Company. Sheryl enjoys traveling, hiking, reading the Economist, and spending time with her large extended family. She lives in beautiful Boulder, Colorado, but is just a phone call, email, or Zoom away!