Octavia Hill was born in Wisbech, Isle of Ely, Cambridgeshire, the daughter of James Hill, a corn merchant, former banker and follower of Robert Owen, and his third wife, Caroline Southwood Smith. He had been widowed twice, and had six surviving children (five daughters and a son) from his two previous marriages; Octavia was her father's eighth daughter and tenth child. He had been impressed by the writings on education of his future wife, the daughter of Dr Thomas Southwood Smith, a pioneer of sanitary reform. He had engaged Caroline as a governess to his children in 1832, and they were married in 1835. The family's comfortably prosperous life was disrupted by James Hill's financial problems and his mental collapse. In 1840 he was declared bankrupt. Caroline Hill's father gave the family financial support, and took on some of Hill's paternal role.