"sighting of land," 1620s, also "the first land 'made' on a sea voyage" (1883); from land (n.) + fall (v.) in the sense of "happen." A word from the days of imprecise nautical navigation.
Land-fall. The first land discovered after a sea voyage. Thus a good land fall implies the land expected or desired; a bad landfall the reverse. [John Hamilton Moore, "The New Practical Navigator," London, 1814]