Background
John Chalmers Da Costa was born on November 15, 1863 in Washington, D. C. , United States. He was the son of George Tallman and Margaretta (Beasley) Da Costa. The father at that time was a soldier in the Army of the Potomac.
His original ancestor in America was Isaac Da Costa, who emigrated from England to Boston in 1690, the family being originally Spanish. His descendants lived there until directly after the Revolutionary War, several of them serving in it with distinction. One of these, Joseph Da Costa, a sea captain, married Ann Tallman of Philadelphia, her maternal grandfather being a Chalmers of Scotland, and her paternal grandfather coming from Germany. Of these several strains John Chalmers Da Costa was a descendant.
His father in time became president of the Camden & Atlantic Railroad, and the son grew up in an environment of affluence and literary culture, for the most part the father providing the one, the mother the other. He also acquired at an early age a lasting interest in railroading and in fire-fighting, so that it was not unusual throughout his active life for him to ride locomotives and fire-engines with their crews; his professional services, gratuitously given, were always at their command.