Proxies in the United States
The default direction for almost every data job. Most of the platforms people scrape are hosted here, so latency is lowest and the address rarely looks foreign to the site.
Why almost everyone starts here
Marketplaces, ad networks and search all keep their main infrastructure in the country, so a request from a US address takes the shortest path.
That shows up as time saved on long runs. On a million requests, the gap against a European address adds up to whole hours.
The crowd problem
Popularity cuts both ways. US datacenter ranges are the most heavily used in the world, which means platforms know them best.
Practical effect: a cheap US address is more likely to arrive already flagged than a cheap address in a quieter country. Spread across subnets matters here more than anywhere.
Regions inside the country
For local search results and store pricing, the state matters. Prices and availability differ between coasts on the same retailer.
If your job depends on that, pin the location deliberately and check what the vendor actually assigned.
Sizing a pool
Forty to eighty addresses covers a daily catalogue sweep at a normal pace. Anything larger is driven by the rate limit the platform sets.