If you would like to know the IP Address and Location of email sender in Gmail, Google Scripts can help. It extracts the raw headers of the email message and then pull the IP address of the sender using regular expressions.

The IP address is then passed to a free GeoIP service that gives the geographic location of an IP address. The JSON response may contain the country name, city and even the zip code in some cases.

Also see: Find Person by Email Address

function getEmailCountry(messageID) {
  var message = GmailApp.getMessageById(messageID);
  var raw = message.getRawContent().split('\\n');

  for (var j = 0; j < raw.length; j++) {
    var ipaddress = /Received:\\s+from.*?\[((?:[0-9]{1,3}\.){3}[0-9]{1,3})\]/i.exec(raw[j]);

    if (ipaddress != null) {
      var json,
        reply = { country_name: 'Unknown' };

      try {
        json = UrlFetchApp.fetch('http://freegeoip.net/json/' + ipaddress[1]);
        reply = JSON.parse(json);
      } catch (e) {}

      Logger.log('The email is sent from ' + ipaddress[1] + ' in ' + reply.country_name);
      break;
    }
  }
}