In most cases, no. It’s not a crime to be walking the streets of New York without identification. You also don’t have to show ID to a police officer if you are asked, however, if you are arrested for another reason the police may detain you until you can be identified (which could take 72 hours). Also, police cannot ask you to show identification unless they have a reasonable suspicion that you’ve committed a crime. If you are asked to show identification, and feel that you are being detained, simply ask the police officer if you’re free to go.
If you are detained and haven’t shown any identification, you will have to decide whether or not to show identification. If it’s a simple mix-up, you may wish to show identification to get it resolved. However, if you are fearful about revealing your identification for other reasons, it may be better to not show any ID.
A couple of exceptions do apply to the general rule that you don’t have to carry ID. If you are driving, you must be able to show a valid driver’s license if asked. Also, passengers on commercial airlines can be required to show ID.
There is also a law in New York City that requires public transit riders to carry identification. However, the law was recently declared unconstitutionally vague, and it was struck down. The judge found that it was a criminal law that penalized conduct that is constitutionally protected. It was also found to give almost unlimited discretion to the NYPD. Therefore, public transit riders in New York City cannot be forced to carry or show identification.