If you send emails from StartMail.com, no US government agency or any other party will be able to identify you, your IP address, or your country location. StartMail.com never records or saves a user's IP address. IMO, StartMail probably is the most anonymous, most private, and most secure email service provider available anywhere. StartMail has built-in PGP encryption. You can send encrypted emails or send emails in clear text. You can send encrypted emails to recipients who do not use or do use PGP encryption. If your recipient does not use PGP encryption on his computer, he still will be able to read your encrypted message. The StartMail annual subscription cost is Euro €49.95 or US$59.95. A StartMail 7-day trial version is free.
The StartMail servers use an outstanding level of secure HTTPS encryption for all Internet connections: (TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 128 bit keys, TLS 1.2). If you run the 2-minute QUALYS SSL LABS SSL Server Test online test on the www.startmail.com server, the site easily achieves a rare A+ grade, which is superior to the A grade you will see after you run the same 2-minute test on the NSA www.nsa.gov server. After you read the StartMail Privacy Policy, there's a good chance you will decide to register a StartMail account. StartMail is a company in the Netherlands beyond the reach of US laws, beyond the jurisdiction of the NSA, and beyond the reach of the US FISA court.
Of course, you can connect to the StartMail site with Tor or Tails to send emails, which increases your assurance of anonymity even higher than the highest level.
Even if the 101st Airborne Division parachuted into the offices of StartMail in the dark of night and confiscated all of the StartMail email servers, they would find nothing more than a big fat blank because StartMail never records or saves IP addresses. I have been using StartMail for years, especially when I want to send 100% anonymous emails. The Dutch people and their government are ferocious about protecting their right to personal privacy, personal anonymity, and personal liberty.
(If you visit the StartMail site, you might as well visit its sister site, startpage.com, which is an Internet search engine within the same organization in the Netherlands. I have been using the sister Internet search engine eu.ix.quick.com for more than 7 years. Recently, eu.ixquick.com changed its server organization, which facilitated my migration to the sister startpage.com. I use no other search engines. The Internet servers are in the Netherlands beyond the reach of the NSA and other spies. However, like with StartMail, the 101st Airborne Division would find only a big blank because the servers never record IP addresses, search history, or any other personally identifying information. The startpage.com search engine and its sisters truly provide 100% anonymity and secure SSL HTTPS encryption as strong as StartMail.)