An email is supposed to be a method of communication between two people, who are most often acquainted. But sometimes anonymous emailers send you messages. Some email accounts, like school or work email accounts, are easy to trace. Unfortunately, with so many providers offering free email accounts, emails themselves can be difficult to trace. No matter what email account was used, it is possible to find the IP number for it, which should give you some clues.
Open the email and see what type of information came along with it. You should see a series of names and numbers. Depending on your email program, you might have to expand the information by clicking "read more" or "show details" or "show more" or any other link that provides access to more information about the sent email.
Scan through the list of names and numbers until you find a "reply to" address. It could be that this "reply to" address is one you recognize. If someone sent you an email from another account, but didn't change his "reply to" address, you might be able to find out who sent it. Below these should also be things like "sender" and "name." All of these things can be changed by people who understand computers, so if you don't find out who sent it from this information, keep looking.
Find the IP address. In many sent emails information, an IP address will be listed twice. The first one on the list is easy to manipulate by someone well versed in computers, so if there are two IP addresses listed, take the one that appears last.
Plug the IP address into an IP address "lookup" site. There are dozens of such sites from which to choose (see Resources). Some services are free and some require payment.
Check the information that comes back. Although you can find information about the IP address, the information is that of the actual Internet Service Provider, not of the person who sent the email. So, you will need to call the provider and ask about the particular email address. Or perhaps just the location of the ISP can give you enough information as to who sent the email.
Unfortunately, if a person uses a free web-based email account, and uses the Internet at a coffee shop or a place where many people have access to the same computers, an anonymous email can be impossible to trace. If you've tried all of the suggestions and can't get answers, you may be out of luck.