Adelia Sarah Gates (October 24, 1825 - September 21, 1912) was an American illustrator of botanical specimens. Her early work was as an elementary teacher and decorative watercolorist.She was an amateur decorative watercolorist and painter long before she was able to advance further into scientific illustration methods and to travel widely on collecting and documentation expeditions later in her life.She was born in the Susquehanna Valley.