A related thread: small rural town drops off the map- plausible? - Cafe Society - Straight Dope Message Board
Does Burning Man have a place here?
Almost 50,000 participants.
Cahokia once had a population of about 40,000. Now it’s an archeological site.
Time magazine is a doing extensive reporting on Detroit, including buying a house and reporting from it for a year. One plan was to concentrate the population into a downtown and raze building in a ring around the city that would be turned into parkland. Here is a link http://www.time.com/time/nation/article/0,8599,1925796,00.html
Didn’t they move Springfield five miles down the road from its original location?
Hasn’t Utica, NY all-but-vanished?
That’s really odd to me, since San Jose is much larger than SF and Oakland has its own identity and major sports teams. But I can’t be really be objective about it, as a (former) resident of SF.
::wondering if people really think that::
As far as annexation goes, Brooklyn was much further up the list of largest cities in the US shortly before 1900, since its population was over a million before it became part of New York City in 1898. However, last time I visited, Brooklyn did not appear to have become a ghost town, so I don’t think annexation counts.
Not sure if this counts:
When Europeans and Americans started coming to Hawaii, 1 million of the 1.2 million natives were killed, mostly by communicable diseases, within (iirc) 2-3 generations.
Currently, the population of Hawaii is ~1.2 million.
How about a city that never was? Elko Tract, Virginia.
I certainly do. I mean, yes, I know they’re separate cities but they’re all filed under “Greater San Francisco” in my mind’s geographic database.
And I’m still surprised how many Americans cannot name any cities in Australia besides Sydney. 
Chicago has lost 900,000? You sure about that?
Apalachicola, Florida was once a thriving cotton port on the Gulf of Mexico (cotton was floated down the Apalachicola River from Georgia and Alabama). When the railroads came, Apalachicola dwindled in importance and population. Today it is a sleepy fishing village of 2,000. There are a lot of vacant “city” lots that have reverted to native vegetation. I’m having a hard time finding out the city’s population at its peak, but there has been considerable shrinkage.
As for what happens to a city’s land when it shrinks, you can end up with a lot of vacant lots like Apalachicola, or the city can exercise eminent domain and clear blighted sections for parkland, redevelopment, or other use. The precedent for this was set in the 1954 Supreme Court case of Berman v. Parker in which the Court cleared the way for the District of Columbia to redevelop large swaths of blighted land via eminent domain.
Driving back from Austin, TX to San Diego, CA in 1998, we ALMOST stopped in a town called Sierra Blanca, TX that is apparently the site of one of the largest sewage dumps in the U.S. - part of some kind of deal where a company dumped large quantities of waste from New York in the West Texas desert.
I don’t know how big the town was at it’s peak, but at the time we stopped there, we had never seen a place quite so spooky in our lives. Most every building in downtown was boarded up with ‘no nukes’ and ‘no dump’ spray-painted on the boards. We high-tailed it out of there and stopped for the night in El Paso instead.
And there I was looking for a “quaint” town to stop in for the night. Maybe if you’re filming a zombie apocalypse movie…
Woodstock had 400,000 for a weekend.
Centralia, PA keeps hanging in there. It is still a legal borough of Pennsylvania, even with 9 denizens. The Mayor of Centralia, the last I checked, is 90 years old. There has been no real effort that I am aware of by any of the adjoining townships or the adjacent Borough of Ashland to annex Centralia, because frankly the land and tax revenue potential of it is completely worthless. If you are ever in the area, I’d recommend a drive-through and a hike of old route 61, it will totally creep you out.
Centralia is part of Pennsylvania “Coalcracker” Country, and there are other former mini-cities up there that lost the bulk of their populations when they hit the ass end of the coal mining industry: Mahanoy City (16,000 to 5,000 in 60 years) , Shenandoah (30,000 to 5600 in 80) come to mind. Recently, there has been an influx of Mexican migrants who have purchased many homes on the cheap in the area, which has introduced many racial issues over the past 2 years.
People outside the US, yep.
I must admit that while I am aware that San Jose is a separate entity than S.F. I tend to think of them as one. Oakland does retain (somewhat) as separate identity in my mind. But if you asked me what exists near the bay besides S.F. I would be hard-pressed to name anything. And I have visited S.F. several times and love the place. But it is like thinking of New York vs New York New York… 
Again, not a US city, but otherwise relevant…
[URL=“Dunwich - Wikipedia”]Dunwich
Please excuse my coding…