Large whiskey bottle (Fallout 3)

The large whiskey bottle is a common item in Fallout 3 and Fallout: New Vegas.

Fallout 3
It's useful only as Rock-It Launcher ammunition. They can be found in every settlement and many ruins.

Fallout: New Vegas
The Honest Hearts add-on introduced a recipe for large wasteland tequila which requires this item, making it significantly more useful.

The Old World Blues add-on allows the player to refill this item at the Sink, creating purified water.

Fallout 3

 * 27 bottles in Tenpenny Tower
 * 10 on tables/counters in Rivet City's The Muddy Rudder
 * 8 in The Ninth Circle
 * 8 in Dukov's Place

Fallout: New Vegas
Large whiskey bottles can generally be found in areas with large amounts of empty whiskey bottles, only in smaller numbers.
 * Two are found right next to the campfire near the Goodsprings Source fast-travel point.
 * The casino area of the Lucky 38 contains a full dozen on a set of shelves behind one of the counters.
 * Many can be found alongside several empty whiskey bottles in the mining carts just outside of the NCR Correctional Facility main entrance.
 * There are many in one of the houses in Higgs Village in Old World Blues.
 * Many Ranger stations have one near the comm officer.
 * The members-only dining hall of the Ultra-Luxe has nine on a shelf in front of the door to the kitchen.