Ask HN: What would happen if an EMP were detonated over the United States?

It depends a lot on the power and placement of the EMP, as well as when it went off. There are a lot of scenarios in which it just wouldn't be that bad. Just for fun, let's muse on the worst-case scenario: all except specially shielded (mostly military) electronics would become non-functional, and replacing all that would take serious time and money. Money, by the way, that we can't get to because all of our banking systems are electronic, and that may not have much real value after such a disaster.

I know a few of my fellow hams who still maintain very old-school rigs that wouldn't be affected beyond hand repair by an EMP. The country would pretty much rely on us for communication.

Without a working car, my son and I would be left on foot to get to the family farm, unless we could trade for horses along the way. Once there, living off-grid isn't a problem. My grandparents never fully trusted modern technology, so my brother and I were schooled in preserving food without power, cooking, heating/cooling a home off-grid, and so on. If this happened in the middle of a harsh winter, we'd face a couple of hard months before scaling up our farm and food preservation efforts, but having confidence that it was temporary would do a lot to get us through.

Not only do all of these give us a way to survive, but they give me things to barter for what we don't have or can't produce.

Cities would have riots, starvation, dehydration, and disease. Suitably rural communities would get by okay, and possibly prosper, under such conditions. City life is just plain unsustainable -- there's nowhere to grow/raise adequate food, no one is taught life skills like growing/raising food (or they rely on commercial fertilizers, garden hoses, etc. to do so), preserving food without electric refrigeration, and so on. Even disposing of sewage and getting clean water depend on electronic-controlled infrastructure. Garbage would pile up like mad without trucks to come get it.

An acquaintance of mine once asked what he should do in such a doomsday scenario. I told him that there was really no way he'd survive, as he lacked any useful skills. He pointed out that he was an extremely good coder, and I asked him what he was going to program. He asked if he could come to the farm with me, and I explained that we can't afford to take on people who aren't prepared to lend anything to our survival.

It varies a lot by scale, the type of land, and what other resources are available, but as a rough estimate you need about 1 acre per person you wish to sustain at a bare minimum. On a smaller scale, with less-than-ideal land, or with inexperienced/incompetent farmers, you need much more than that. If you want someone with those resources to let you make a home on their property (we WILL shoot you if you try to trespass and take resources), you'd better have something to offer in return.