Seward was the elder of two surviving daughters of Thomas Seward (1708–1790), a prebendary of Lichfield and Salisbury and author, and his wife Elizabeth. Elizabeth Seward later had three further children (John, Jane and Elizabeth), who all died in infancy, and two stillbirths. Anna Seward mourned their loss in her poem "Eyam" (1788). Born in 1742 at Eyam, a small mining village in the Peak District of Derbyshire, where her father was the Rector, she and her sister Sarah, some 16 months younger, passed nearly all their life in that relatively small area of the Peak District of Derbyshire and in Lichfield, a cathedral city in the adjacent county of Staffordshire.