Born Maria St. Clair Whitney in Eagle Harbor, Orleans County, New York on January 21, 1845. (She was shaving 20 years off her age by 1910.) Educated in Albion, New York.
Sometimes, she wrote poetry under the name "Egypt," and may have painted under that name also. She married George Edwinton Hall at Eagle Harbor on May 5, 1870 and then lived in New York City, studying painting at the Art Student's League from 1878 to 1880 with William Merritt Chase. In 1882 she married a noted Boston physician, Dr. Nathaniel Waldo Emerson.
Emerson had a career as a newspaper and short story writer in Washington, DC circa 1905. She moved to Los Angeles, and was a divorced artist in the 1910 census. Emerson founded and was president of the American Woman Film Company in 1916. On May 23, a truck returning from locations shooting near Los Angeles with crew members of the first proposed film "Saul of Taurus" overturned, with many injured. The company was disbanded and the film never completed.
Information provided by Tom Taber, who published a book of Civil War letters and Emerson, Whitney at the time, was living at the house of the woman who wrote those in 1865. (Hard Breathing Days: The Civil War Letters of Cora Beach Benton, Albion, New York, 1862-1865)