I don't have a lawyer. I'm not rich enough to have one on retainer. The only ones I see ads for are personal injury and DUI lawyers. Who would I call, and how would I know to call them?

I'm not that kind of lawyer, so don't call me! But I do know the answer to this.

If you're in jail, you are usually allowed multiple phone calls in order to obtain counsel (it's not just "one" phone call). You're probably best off calling whoever you're closest to that's not in jail with you, like a relative or a close friend, and explain your situation and ask them to do some research and find you a good lawyer. If not, many jails will have lists of criminal defense attorneys or attorney referral services - even advertisements in the area where the outside phones are for making such calls.

I can't offer too much visibility into what ICE would do. Google's AI Slop Machine tells me that ICE detention facilities are supposed to offer similar access to telephones as jails do - detainees are to be provided unmonitored telephone access to legal counsel. ICE was playing a lot of games with that in certain circumstances, but I suspect it wouldn't be too difficult to make them concerned that they might actually have a U.S. citizen on their hands and might need to let you place a phone call to counsel. It might not be quick or convenient, but you should be able to get on a phone with a lawyer in due course.