The Gentilly neighborhood is bounded by Lake Pontchartrain to the north, France Road to the east, Bayou St. John to the west, and CSX Transportation railroad tracks to the south.

The east-west streets are Lakeshore Drive, Leon C. Simon, Allen Toussaint Blvd (a section of which was formerly called Hibernia), Prentiss, Harrison, Filmore, Mirabeau, Hayne, Chef Menteur, and Gentilly.

The high ground became Gentilly Boulevard and U.S. Highway 90, part of the Old Spanish Trail from St. Augustine, Florida to Los Angeles, California.

Settlement was originally mostly confined to along the long narrow ridge, plus Milneburg, built on elevated piers on the shore of Lake Pontchartrain.

Some older New Orleanians extend the definition even further, to include the section of old Gentilly on the east side of the Industrial Canal, now part of Eastern New Orleans.

By this reckoning, Mirabeau Gardens,[2] Vista Park and Oak Park, lying between the London Avenue Canal and Bayou St. John, fall outside of Gentilly, as do the Lakefront subdivisions of Lake Terrace and Lake Oaks, and the Lakefront campus of the University of New Orleans which doesn’t necessarily imply that these areas are disregarded as a “part” of Gentilly.

On February 13, 2007, an EF2 tornado struck the Pontchartrain Park neighborhood in the town, many FEMA trailer created after the storm were heavily damaged or destroyed, including one where an elderly woman was killed.

[3] Bus service from the New Orleans Regional Transit Authority (NORTA): Gentilly is bounded by Lake Pontchartrain to the north, Interstate 610 to the south, City Park to the west, and the Industrial Canal to the east.

The "design-build" process, one specially allowed only in parishes affected by Hurricane Katrina under Louisiana law, was used to rebuild this library and four others.