Manoel Pinto da Fonseca (10 October 1804 – 20 October 1855) was a 19th-century businessman described as "the most notorious slave dealer in all Brazil".^[1] His business was a "highly organized mercantile house capable of operating on four continents" and may have had up to 50 employees.^[2]

Da Fonseca was born in the Porto region of Portugal in 1804.^[3] He entered the business around 1837 in company with his brothers.^[4] According to a British report based on a declaration by Da Fonseca, his profits in 1844 were £150,000.^[4] He trafficked enslaved people from Angola and the coast near the Congo River.^[2] In 1844 or 1845, Da Fonseca bought the slaving brig Uncas from Cuban shippers who had in turn bought it from American slave trader William H. Williams of Washington, D.C.^[5] Porpoise and Kentucky were also Da Fonseca's ships.^[6]

Da Fonseca's major competitors in Brazil were José Bernardino de Sá and Tomás da Costa Ramos; all three hired U.S.-flagged ships and American captains and sailors during what was known as the "contraband era".^[7]

Da Fonseca was deported to Portugal in 1851.^[2] He died in Paris in 1855.^[3]

• Atlantic slave trade to Brazil