A small twin-engine plane crashed in a muddy field on Saturday near the town of Copake, N.Y., killing all six people on board — two surgeons, two of their children and the children’s partners, according to a family member of the victims.

The plane, a Mitsubishi MU-2B bound for Columbia County Airport near Hudson, N.Y., was carrying the three couples en route to a 25th birthday celebration and Passover Seder, according to a statement from a family member.

Michael Groff, the pilot, was a neurosurgeon and experienced flyer, and his wife, Joy Saini, was a pelvic surgeon. Their daughter, Karenna Groff, was a medical student at N.Y.U. Langone and a former star soccer player at M.I.T., where she was named N.C.A.A. Woman of the Year in 2022.

Ms. Groff’s partner, James Santoro, was an investment banker and had planned to propose marriage this summer, the statement said.

Ms. Groff’s brother, Jared Groff, was a paralegal at a New York hedge fund who had been planning to attend law school in the fall. His partner, Alexia Couyutas Duarte, was planning to attend Harvard Law School this fall.

Their deaths and identities were confirmed by a family member, Jonathan Becker, a vice president for academic affairs at Bard College. “We will remember them as the six brilliant, dynamic and loving people that they were,” he said in a statement.