N.Y. Penal Law § 140.10

§ 140.10 Criminal trespass in the third degree.
  A person is guilty of criminal trespass in the third degree when he
knowingly enters or remains unlawfully in a building or upon real
property
  (a) which is fenced or otherwise enclosed in a manner designed to
exclude intruders; or
  (b) where the building is utilized as an elementary or secondary
school or a children's overnight camp as defined in section one thousand
three hundred ninety-two of the public health law or a summer day camp
as defined in section one thousand three hundred ninety-two of the
public health law in violation of conspicuously posted rules or
regulations governing entry and use thereof; or
  (c) located within a city with a population in excess of one million
and where the building or real property is utilized as an elementary or
secondary school in violation of a personally communicated request to
leave the premises from a principal, custodian or other person in charge
thereof; or
  (d) located outside of a city with a population in excess of one
million and where the building or real property is utilized as an
elementary or secondary school in violation of a personally communicated
request to leave the premises from a principal, custodian, school board
member or trustee, or other person in charge thereof; or
  (e) where the building is used as a public housing project in
violation of conspicuously posted rules or regulations governing entry
and use thereof; or
  (f) where a building is used as a public housing project in violation
of a personally communicated request to leave the premises from a
housing police officer or other person in charge thereof; or
  (g) where the property consists of a right-of-way or yard of a
railroad or rapid transit railroad which has been designated and
conspicuously posted as a no-trespass railroad zone.
  Criminal trespass in the third degree is a class B misdemeanor.