Monuments
In 1875, she submitted a model sculpture of Charles Sumner for a blind competition conducted by the Boston Art Committee. She knew Sumner, a senator and abolitionist, through her brother Alexander, who was a classmate of Sumner's at Harvard University. Whitney's model competently captured Sumner's frame and features. She depicted him seated in a chair, in part because of ancient Greek artist's practice of portraying prominent people seated to "represent dignity and something of state." She won the contest, including receiving the prize money, until the judges realized that they had selected a work made by a woman; they thought it would be inappropriate for a woman to sculpt a man's legs. The judges rejected her offering and selected Thomas Ball's sculpture for the Boston Public Garden. Both the Sumners and the Whitneys were disappointed, but Whitney wrote in a letter, "Bury your grievance; it will take more than the Boston Art committee to quench me."
She exhibited the model of Sumner at the Centennial Exposition of 1876. Following an 1879 exhibit of the model, the New York Evening Post stated of the judge's decision, "Think of a woman bringing her mind to bear on the legs of a man-even if those legs were inside a pair of stone trousers! New York Evening Telegram wrote a verse which starts out: "You see, ’tis a fixed law of art, my friend, / That only a man can superintend / The play of muscle and post of limb, / Whenever a statue is made of him." The verse later states "Yet under the dome of the Capitol / Stands Samuel Adams erect and tall, /
As free as his namesake before the fall; / And though the image was carved by woman / Rarely is marble so grandly human."
Among her well-known public monuments is the statue of Samuel Adams (1876) in the National Statuary Hall Collection in the US Capitol, Washington, D.C. Whitney traveled to Italy in 1875 to acquire the marble for the sculpture. During the trip, she studied French sculpture techniques at Écouen, realized in her work Le Modèle, which was created with a degree of Realism. A bronze and granite replica (1880) of the Samuel Adams sculpture is installed in Faneuil Hall Plaza in Boston, where Adams gave speeches about British rule and taxation.
Another important work is the statue of Leif Erikson (1887) in Boston. She corresponded with Frederick Law Olmsted about the placement of the monument and its landscaping. Another edition, Leif, the Discoverer, was placed in Juneau Park in Milwaukee, Wisconsin.