Clarissa Down(e)s was born in 1786 in Boston, the daughter of Shubael Downs and Lydia Bangs. She appears to have been a student at Mrs. Rowson's Academy in Roxbury, Massachusetts in 1805, as cited in Glee Krueger, New England Samplers to 1840 (Sturbridge, Massachusetts, 1978), p. 162. It is probable that she worked these two samplers there, in honor of her father and mother who died in 1790 and 1804, respectively.
She married Lemuel Grosvenor (1784-1858) of Pomfret, Connecticut around 1808, in Boston. They resided in Pomfret, Connecticut. The talent for needleworking appears to have run in the family, as Clarissa's maternal grandmother was Desire Dillingham (1729-1807), who stitched a Fishing Lady needlework now in a private collection but once exhibited at the Museum of Fine Arts, Boston and illustrated in Gertrude Townsend, "An Introduction to the Study of Eighteenth Century New England Embroidery," Bulletin of The Museum of Fine Arts (April, 1941), pp. 19-26.
For more information on Mrs. Rowson's Academy, see also Betty Ring, Girlhood Embroidery (New York, 1993), p. 88.