Can a website really block all US IPs? How effective is it? or How does a website can block all US IP

OP here—thanks for all the replies! Super helpful.

So sounds like a website can block all US IPs *in theory*, but it’s never gonna be 100%. VPNs and proxies are the main killers.

Might give Cloudflare’s geo-blocking a shot since a few of you mentioned it.

Follow-up Q: Anyone know if residential proxies slip through these blocks easily? Or are they usually caught too?