Sometimes, you get an e-mail, and you don’t know who sent it. In this case you have to find the location of the e-mail sender, so you can guess who the person might be.
To find the location, you need to find the sender’s IP address. Gmail does not include the sender’s IP address in the message when using the Gmail web interface for e-mail.
When the person uses desktop clients such as Mozilla Thunderbird or Outlook to send e-mails, the IP address is often included in the message.
Find the IP address of the email sender in Gmail
Log in to your Gmail account.
Open the email and click “More” (inverted triangle next to Reply).
Click “Show original.”
In the next window press Ctrl + F and search for “Received: from” without quotation marks. You may see the IP address of the sender.
If many cases of “Received: from” appear on the page, select the last one. Now, you have to track the sender’s location by IP address.
Go to the IP-Tracker website to find the location of the IP address.
Enter the IP address you found in Gmail.
The tool now displays information such as city, country, time zone and ISP. With this information, you will be able to find the location and probably the person who sent you this email.
Read here: How to delete all emails in Gmail