If you are being called by someone with a phone number that starts with area code 212, or you need information on a person who has this kind of cell phone or land line number, its not surprising. 212 serves a part of Manhattan in New York state, so the odds of you finding out who it is immediately are about 1 in 1.6 million people.
NANP, which stand for the North American Numbering Plan went into effect in 1947, and at that time because population numbers were so different than they are now, there wasn't the need for nearly as many area codes as we have now. That being said, 212 is very old and premiered in 1947 with the original assigned telephone codes.
Area code 212 also has an overlay of 646 and 917, making things just slightly more complicated if you are looking for someone. However, it can easily be said that twp of the areas that are served by 212 are Queens and the Bronx.
Considering that New York is so massive in population, you might be cringing by this point at the thought of trying to locate information about someone in this area using only the phone number that you have on hand.
The solution to this is really quite simple. You can just take that number and do a reverse lookup on it using a reverse phone number search site. These are a dime a dozen, however there are some really good ones that will provide you with valuable information.
Free reverse lookups are not nearly as effective, because its required that a small fee be paid to get personal details on someone based off of their phone number, so as you can imagine - any free reverse phone number lookup that you try to use with area code 212 is going to provide you with slightly limited information.
The kinds of details that you should be able to get with a paid lookup, which costs very little to use and has many benefits, are typically the name of the person who uses the phon number, their address, carrier that they are with, and maybe even really important back ground information which sometimes can surface in the mix of things.