You only hear about the Eastern Seaboard. What’s special about the Atlantic coast of the United States that makes it a “seaboard?”
Are there any other “seaboards” in the world?
Maybe the same reason there is no Atlantic Northeast?
Probably for the same reason people say “there’s no east side of Chicago.” Of course there is, there’s an east side to everything.
But people also say “I’m catching a plane for the coast.” They mean the Pacific coast.
It’s just a term that’s become associated with the area.
Like when I say “the South,” I wouldn’t include any part of Florida from Orlando on south and I wouldn’t include Jacksonville, but those are obviously part of “the South.”
But they were settled en masse by Northerners.
Just a WAG, but it may be because “seaboard” seems like a fairly old-fashioned term, and the Eastern coast was populated first, back when shipping was the primary means of transportation. Plus, at that time most immigrants came from Europe. So the Atlantic remained the “default” body of water bordering the U.S. . . . the “sea bo(a)rder,” if you will.
I would say that when talking about “sides” of a city, you mean that direction from the downtown, or, possibly, a term commonly used to by the locals whether it makes directional sense or not. So Chicago doesn’t have an “east side” - it isn’t a commonly used local term, and east of the downtown is in Lake Michigan. Paper Lace was apparently singing about a war between gangster fish. Or a Chicago in the same alternate universe where Perry Como observed that “The bluest skies you’ve ever seen are in Seattle”.
Except the poles.
Ireland has a western seaboard. In fact, when I do a google search for “western seaboard” (admittedly on google.ie) the positive results refer almost exclusively to Ireland.
Maybe… I can czech.
I was taught in Jr. High that it was because most of the Eastern Seaboard was settled by Northern Europeans, (maybe Dutch ‘zeeboarden’), while the west coast was mostly settled by the Spanish, (hence ‘costa’). I don’t know Dutch or Spanish, so what I was taught could be so wrong.
“…born and raised in South Detroit…”
– Journey
Why is it a seaboard when it’s on an ocean?
Beat me to it 
I’d say you’re on to something. Starboard means “the steering side” which for right handed people is the right side of a ship.
Seaboard would mean “the side the sea is on” but might not make it into west coast parlance.
Look at the Eastern Seaboard. The look at the West Coast. There is a notable difference.
The Atlantic coast of the country is quite thoroughly populated, all the way from Florida on up. Especially, from Newport News up to Maine, there is considerable commercial activity all along the coast, either through shipping or through vacationing.
By comparison, the West Coast only has pockets of humanity on it. San Diego, then the LA area, then a big skip to Santa Barbara, which isn’t that big a pocket. Then a LONG jump to San Luis Obispo, then another VERY long jump to the Monterey Bay. Another longish jump to the San Francisco Bay. Etc., all the way up the coast.
So the West Coast is not an inhabited area, not commercially important, etc.
If you think that’s bad, our Eastern Seaboard is on a gulf, the Gulf of Thailand.
How does that impact the terminology used in referring to the two regions? Does the word “seaboard” carry some related connotation?
ETA: OTOH, Satchmo appears to make a good point – if indeed it isn’t a sort of cultural retcon. (Not an accusation, just an observation that spurious popular expanations often arise that way and make their way even to the schools.)
My daddy was a cop. On the East Side of Chicago. Back in the USA. Back in the bad old days.
LA and Long Beach are very busy ports, probably a lot of Chinese stuff passes through there. Seattle has a pretty big port too.
Well there IS an East Side (Wikipedia) of Chicago
What I think DSYoungEsq is referring to is the fact on the West Coast you only have San Diego, LA, and San Francisco. Portland is inland and Seattle and Vancouver are not directly on the ocean. And eve in SF, Oakland is the main port area which not directly on the bay. Stockton inland is a big port and that’s inland too.
But on the east coast from Boston to Miami, it’s pretty much populated and the barrier Islands are small (excepting Long Island) where on the West coast Seattle and Vancouver are inland by huge barrier islands.
On the East Coast only North Carolina lacks a main city on the coast. (Wilmington NC has a hundred thousand but isn’t big compared to the other NC cities).
I’m speaking roughly here
“‘Western seaboard’ scotland” pretty much matches “‘western seaboard’ ireland” - to have a tradition of such naming, I guess there’s got to be (a) more than one coast, (b) a maritime history, and (c) English as a local language. There’s quite a few results originating from India in similar searches on that country, for example. (Edit: and I suppose there’s not the same maritime history on the west of America as on the east, even though modern shipping is important.)