[nradov]

In many US cities, low lying areas near water (rivers, large lakes, oceans) were often used as cargo ports. Factories and other industrial facilities were then built nearby which made it easier to obtain raw materials and ship out finished products. And naturally low wage, blue collar workers tended to live near those jobs. Such areas were also at greater risk of flooding, and suffered more from air, water, and noise pollution. So, affluent people tended to build homes on higher ground away from the dirty waterfronts.

Now that trend has somewhat flipped. The US has deindustrialized and offshored most heavy industries. Stricter environmental laws have reduced pollution. And civil engineering measures have somewhat reduced flood risk. So, now waterfront residential areas have become expensive and fashionable.

This is just a general trend. We will still see exceptions in SF and other cities.

[chubot]

Two good examples of the flip are the Ferry Building in SF and Chelsea Market in Manhattan. Those used to be big industrial / shipping / cargo buildings but now sell upscale food :)

It's kind of funny how you see the same economic patterns play out in different cities over hundreds of years

Another pattern is that train stations and big US post offices are often in the oldest parts of town, and I think they have started to move over the years. That real estate is often extremely valuable, so the govt or business finds something else to do with it