The novel opens by describing the varying fortunes of the Ward sisters. Thirty years earlier, Maria Ward married Sir Thomas Bertram, owner of Mansfield Park, a grand estate in Northamptonshire, England. Another sister married Sir Thomas’s friend, Mr. Norris—a clergyman man of modest means who was reverend of Mansfield Parish. Frances Ward married least advantageously to Mr. Price, a poor sailor.

Eleven years after her marriage, Frances writes to Lady Bertram for help. Her ninth child is due, and her unemployed husband spends their small income on alcohol. Frances asks her sister if Sir Thomas could employ one of her elder sons in his West Indies business. The Bertrams send money and advice to Frances. However, Mrs. Norris asserts they should do more, proposing they could jointly take on guardianship of Frances’s eldest daughter. Sir Thomas is concerned that his sons may fall in love with their cousin and marry beneath them. Mrs. Norris assures Sir Thomas that the Bertram boys will consider their cousin a sister.

Mrs. Price happily agrees to the arrangement. Sir Thomas is surprised when Mrs. Norris declares their niece must stay at Mansfield Park indefinitely, as she cannot afford to keep her.