When someone moves without leaving a forwarding address, it doesn't mean that you've lost contact with that person forever. The U.S. Postal Service will forward mail to anyone who has supplied a change of address and, if you use the "Address Service Requested" procedure, will send notification of the new address to you, too. You can also use a people-finding website to look up someone's current address, or hire a private investigator.
Send Mail to Your Friend
Write a letter to your friend. Fill out the envelope with the person's name and last known address and include your own name and address in the top left-hand corner. Affix a stamp. Type the phrase "Address Service Requested" in a prominent place on the front of the envelope, referring to the Postal Service website for placement instructions. If the person has notified the post office of his change of address, the post office will attempt to deliver the letter and should also notify you of the new address. There's generally a fee if the person moved more than 12 months ago. This is usually around 2.4 times the original postage cost.
Try a People-Related Search Engine
Use a people-finding search engine such as ZabaSearch or Whitepages. Type the person's full name and city into the search box to see what comes back. A free search will generally pull up the person's current address and telephone number. You should also get a list of past addresses so you can verify that you have found the right person. You can also do a reverse search by typing in the person's last known address or phone number.
Dig Deeper With Pipl
If the regular people-finding sites don't work, try Pipl. Pipl aggregates data from the "deep web," namely, webpages that aren't indexed by Google. For example, it might search databases, social media profiles and forums to build a full profile of the person you're trying to locate. Search by typing in the person's name and city. The way the algorithm is set up, you'll likely get a telephone number, date of birth, photo and employer as well as a current address.
Hire an Investigator
If it's extremely important that you find someone's current address to, for example, serve legal papers, consider hiring a professional people-finder agency. While private investigator services can be expensive, they have access to records, databases and techniques that you do not. It may be worth the additional cost to find someone who is important to you.