Ingersoll was born in
New Haven, Connecticut, son of
Ralph Isaacs Ingersoll, a New Haven lawyer who also served in the state House of Representatives, the United States Congress, and as United States Minister to
Russia and as the mayor of New Haven, and of his wife, Margaret, née Van den Heuvel. His maternal grandfather was
Jan Cornelis Van den Heuvel, a Dutch born plantation owner and politician who served as governor of the Dutch province of
Demerara from 1765 to 1770 and later became a merchant in New York City with the
Dutch West India Company. He graduated from
Yale College at the age of nineteen in 1840. He visited Europe aboard the United States frigate
Preble, commanded by his uncle, Captain Voorhes, for two years, and returned to
Yale Law School, graduating in 1844. ==Career==