Lady Catherine de Bourgh's maid.
Dawson is a minor character who only appears briefly in the novel. We know she is Lady Catherine's lady's maid and that she was scheduled to accompany her employer to London in June. However, Elizabeth Bennet and Maria Lucas decline Lady Catherine's invitation, resulting in Dawson presumably keeping her seat in the barouche.
Due to her limited role, we don't have much information about her physical appearance, personality, or background.