Sir Jonas Moore, FRS (1617–1679) was an English mathematician, surveyor, Ordnance Officer and patron of astronomy. He participated in two of the most ambitious English civil engineering projects of the 17th century: the draining of the Great Level of the Fens and the building of the Mole at Tangier. In later life, his wealth and influence as Surveyor General of the Ordnance enabled him to become a patron and principal driving force behind the establishment of the Royal Observatory, Greenwich.