Ernst Emil Julius Ferdinand Hexamer (Koblenz, 29 May 1827 - Philadelphia, 3 December 1912) was a German-born American civil engineer.

After the collapse of the movement that year he and his brothers fled their homeland, and traveling from Switzerland to the United States.

His elder brother Adolph C. Hexamer became a physician in New York, who published the book Die kinder-cholera oder summer complaint in den Vereinigten Staaten in 1858.

Next he was employed by William Perris Civil Engineer and Surveyor, who in those days published a city plan for New York.

[3] In 1866 he started publishing The Hexamer General Surveys, a series of publications of illustrations of industrial and commercial buildings and properties from the greater Philadelphia area until 1896.