Dewitt C. Peck was born in Oswego County in 1813, where he lived until he was seventeen years old. He then moved to the town of Pompey with his parents, Dennis and Mary (Halliday) Peck, who were natives of Connecticut and Massachusetts. From Pompey they moved in 1832 to Mr. Peck's present place in Dewitt. The father was justice of the peace for many years and at one time coroner of Oswego County. He died in 1852 at the age of 72, and the mother in 1867 at the age of 81. Dewitt C. is one of a family of six children, he and two sisters survive.

In 1840 he married Salome Kinne by whom he had five children:
Herbert D. of Iowa; Albert D. of Montana; Clinton D. of Iowa; Willard H.and Marie E.
He was a farmer his whole life. Served in the Assembly in 1877 and 1878. Died in 1901.