Notable buildings in the city include Freetown Law Courts , the Slave Gate and Portuguese Steps , St John 's Maroon Church ( built around 1820 ) , St George 's Cathedral ( completed in 1828 ) , Foulah Town Mosque ( built in the 1830s ) and the Roman Catholic Sacred Heart Cathedral . Freetown is the seat of St John 's Maroon Church ( built around 1820 ) , St. George Cathedral ( completed in 1828 ) , and Foulah Town Mosque ( built in the 1830s ) .