Fieldston is a privately-owned neighborhood in the Riverdale section of the northwestern part of the New York City borough of the Bronx. It is bounded by Manhattan College Parkway to the south, Henry Hudson Parkway to the west, 250th Street to the north, and Broadway to the east. It is noted for its rural atmosphere, large houses and abundance of trees. The majority of the neighborhood is included in the Fieldston Historic District, designated by the New York City Landmarks Preservation Commission in 2006.

Fieldston is one of a few neighborhoods in New York City that is completely privately owned. The streets and common areas are owned by the Fieldston Property Owners' Association, Inc. which plows the streets, does sewer repair, cares for the trees – of which there are about 1000 – and runs a security patrol as well as other usually municipal functions, such as street repair. Annual dues are paid by the approximately 250 homeowners who make up the Association to maintain the area. Once a year, the streets are closed to non-residents to legally qualify the streets as privately owned; parking is restricted to residents and their guests.