Could someone provide attestation for the "lower part of town" sense? It's not familiar to me as a US speaker. My understanding was that the term originated in Manhattan, where downtown is at the south end of the island (thus lower on the map). -dmh June 28, 2005 17:13 (UTC)
Is the baseball example for the "Noun" section accurate? I would think this usage illustrates the "adverb" more than the "name", doesn't it? --Augustin, October 4, 2010 13:57 (UTC)
Without any evidence, I have a hunch that the above commenter is correct that the origin is from New York's downtown being southward from the rest of it. The Online Etymology Dictionary states that the word originated in 1835, well after the founding of New York, but says that the word is derived from elevations typical of cities, which I personally find less satisfying. They have no citations for that entry. I guess as many cities might be set on a hill as in a valley, although any city that was founded adjacent to a body of water would tend to have a lower elevation in the oldest quarter.