She was first involved with a Sheffield group, which successfully campaigned for people to boycott sugar from the West Indies, as it was produced by slave labour.

Joseph Read had taken over his father's business-[3] which would later become the Sheffield Smelting Company- but later experienced financial difficulties and had to sell Wincobank Hall, which Mary, as the widow of a banker, was able to reclaim.

Rawson was a founding member in 1825 of the Sheffield Female Anti-Slavery Society, which campaigned for the rights of slaves in the British Empire.

[8] The society used lectures and pamphlets to achieve a decrease in sales of slave-produced West Indian goods, such as coffee and sugar.

[2] In 1837 Rawson became secretary of the Sheffield Ladies Association for the Universal Abolition of Slavery,[2] which continued the case for enslaved workers across the world.

[2] The anti-slavery organisations run by women were first started by Lucy Townsend and they were sometimes dismissed as of marginal interest, but recent research has revealed that these groups had a national impact.

[9] Rawson corresponded with figures such as George Thompson in Britain as well as Frederick Douglass and William Lloyd Garrison in the United States.

[13] In 1841, Rawson and her sister, Emily Read, arranged for a day school to be created in the chapel on the grounds of Wincobank Hall.