Are you specifically seeking a Duplex apartment or Town House? They are both very different things and come in very different styles in and around New York City. Many of these found in the historic neighborhoods of NYC are what they call brownstones. A lot of times these types of homes will allow for a separate apartments or multiple apartments in one building. This is what they call a two family or multifamily town house. There are many newer construction duplex homes as well.
Please elaborate on what it is you are inquiring about.
Thanks, and have a great holiday weekend!
Licensed in New York & New Jersey
Licensed Real Estate Agent
Douglas Elliman Real Estate