Hollowed-out rock (Fallout: New Vegas)

Hollowed-out rocks are rocks that have been hollowed out and have items stored in them. 42 of them are found in the Mojave Wasteland and 15 in Zion Canyon.

Fallout: New Vegas

 * Abandoned BoS Bunker: With the small cluster of rocks and shale on the slope leading up to the bunker grating.
 * Black Rock Cave: Just to the north of the fallen radar dish. Directly east from the cave entrance.
 * Bloodborne Cave: Just to the right of the cave entrance.
 * Boulder Beach Campground: By the side of the road, north-west of the jetties, with "The Sun Is Killing Me" graffiti.
 * Bradley's Shack: On the west side of the entrance, by the small valley landslide.
 * Broc Flower Cave: At the foot of the entrance slope, with "The Sun Is Killing Me" graffiti.
 * Camp Guardian: Next to the Camp Guardian population sign, at the base of the path up to Guardian Peak.
 * Cannibal Johnson's Cave: Just to the right of the cave entrance.
 * Cazador Nest: Part of the rock wall, on the east side of the nest alcove, facing back towards the alcove.
 * Chance's Map: Adjacent to the dirt map, with "The Sun Is Killing Me" graffiti on it.
 * Charleston Cave: Part of the rock wall, just to the right of the door, by the heart graffiti.
 * Cottonwood Cove: On the road between the two sets of crucifixion poles, with "The Sun Is Killing Me" graffiti.
 * Crescent Canyon East: On the east exist slope, just after the rail bridge.
 * Crescent Canyon West: In the canyon, on the west exit slope, adjacent to a rusting car husk.
 * Dead Wind Cavern: On the south rock wall slope, around 20 to 30 feet from the entrance.
 * El Dorado Dry Lake: West of the Savaged brahmin, in the sands of the Dry Lake.
 * Fire Root Cavern: At the foot of the entrance slope, on the left.
 * Fisherman's Pride Shack: By the campfire, north-west of the shack.
 * Follower's Outpost: Built into the steps of the signal box structure.
 * Goodsprings Cave: Just to the right of the cave entrance.
 * Hidden Supply Cave: To the right of the cave entrance, with the "no missile" graffiti.
 * Hidden Valley: West of the eastern bunker, with the "no missile" and heart graffiti. You may spawn in front of it when fast travelling to the location.
 * Jack Rabbit Springs: South of the pools of radiation, on the shore of the Dry Lake.
 * Jacobstown: Just outside the perimeter, to the right of the main entrance, where the super mutants stand guard. By the heart graffiti.
 * Lucky Jim Mine: Slightly beyond the shack, near the wooden cart.
 * Makeshift Great Khan Camp: On the west side of camp, near the desert plants.
 * Morning Star Cavern: By the entrance to the cavern, by the bones and the explosive crate.
 * Northern Passage: On the eastern rock wall, near the grave and "The Sun Is Killing Me" graffiti.
 * Powder Ganger Camp East: Next to a Honey Mesquite Tree, around 20 to 30 feet south of the camp.
 * Primm: Attached to a large rock, near the scattered chems and the rock perimeter, above the concrete support wall.
 * Primm Pass: Close to the brahmin bones, on the western end of the pass.
 * Remnants Bunker: About 10 feet north of the entrance, part of the rock wall.
 * Ruby Hill Mine: Part of the rock wall, just to the right of the door.
 * Searchlight East Gold Mine: Southeast of the entrance; climb on the pile of rock and shale to reach it.
 * Searchlight North Gold Mine: On the flat rock bank to the south of the entrance hole.
 * Silver Peak Mine: Part of the wall, just to the right of the shack through which you enter.
 * Techatticup Mine: To the right of the entrance, with the white blocks graffiti.
 * Tribal Village: At the start of the Ravine Path, close to the corpses and tents.
 * Vault 11: Just to the right of the entrance.
 * Vault 22: On the north bank, across from the "Keep Out" sign, by the entrance.
 * Walking Box Cavern: Around 20 to 30 feet east of the cavern entrance.
 * Yangtze Memorial: At the base of the south steps, with the peace symbol graffiti.

Honest Hearts

 * Court Fork Overlook: on the right side of a grouping of boulders immediately south of the blue scenic overlook sign.
 * Dead Horses Camp: above the camp, northwest of the Angel Cave map marker, on the left side of the next plateau beyond the one where the bighorner mother is found.
 * North Fork Bridge: northeast of the bridge, or southwest of Cueva Guarache, off the river shoreline in view of the bridge, between a cliff face and a large boulder.
 * Pine Creek Tunnel on the southwestern/right hand side, just after crossing over the unnamed bridge (southwest of East Fork Bridge) leading to the road to the tunnel.
 * Three Marys on a ledge due south of 3 clustered cliff encampments midway through the river passage.
 * Three Marys on a ledge on the eastern cliff wall heading into the final section of the pass, southeast of the Three Marys map marker.
 * Bighorn Bluff near the cliff wall and a couple boulders at the northwestern end of a small pass a short distance west of the camp and load point/map marker. You could also go west and follow the cliff wall from the Ranger Substation Eagle.
 * Sun Sentinels on a recessed path on the mesa top, south of the map marker.
 * The Spine south by southeast of the map marker between two cliff walls, at the outer edge of the map, not far to the left of a blue hiking trail marker sign.
 * East Fork Bridge on a ledge directly above the northwest end of the bridge. In order to access it, you must walk around the cliff and wind your way up and back towards the bridge. It is possible to become stuck between the hollowed out rock and the cliff face if you jump down from above. Kill any hostiles near the bridge before walking up so that you can fast travel to the bridge if that occurs.
 * Burial Mounds up on a set of steep ramps on the outer cliff wall west of the gravesites. Follow the wall to find the ramps. Alternatively, you may follow the outer cliff wall east from Yao Guai Cave. From there; if you've reached the mounds you've passed the ramps.
 * Clear Water Docks off of the shoreline and next to the cliff wall, in view northeast directly across from the dock.
 * Caterpillar's Mound immediately northwest of the mound, on another hill near the cliff wall. The other rock is directly south within view.
 * Caterpillar's Mound on a ledge a short distance to the southwest of the mound. The other rock is directly north within view.
 * Zion Canyon

Dead Money
While Dead Money doesn't contain hollowed-out rocks, it still follows the same principle of marking stashes with graffiti. There are a total of 13 stashes to be found in the Sierra Madre, some being one or more containers, some simply loose objects.

Lover's mark stashes

 * Medical District: Exit the clinic's back door, go straight across the courtyard to the opposite wall, turn back to the west, facing the door you just exited. Immediately to the Courier's left will be a lover's mark and a medical supply stash.
 * Medical District: Exit the clinic's back door, head north-west through the gift shop and up the stairs, then out onto the roof through a hole in the wall, head straight across from the hole, then look down at the ledge directly above the archway on the opposite side. The lover's mark is on the left wall. Either jump up to the ledge on the left and drop down from there or jump across from the ledge to the right.
 * Puesta del Sol North: At the entrance from the Villa head west through the archway then immediately turn left and look behind the pillar near the tree stump.
 * Puesta del Sol South: Exit the south gate from Puesta del Sol North into Puesta del Sol South, then immediately turn right. Behind the fifth pillar the Courier will find a lover's mark and food items.
 * Note: Across the courtyard due southeast is a poison cloud. Run through it, down a short hall, then through the broken wall and up flights of stairs to the roof where Dean Domino's Strike Up the Band quest is set.


 * Puesta del Sol Switching Station: From the switching station's entrance, walk east and turn around as soon as the Courier enters the first room. A lover's mark is on the power control box that is mounted on the right hand wall as the Courier faces back west to the entrance.
 * Residential District: At the entrance from the Villa turn left and look behind the pillar.
 * Residential District: From the chairs where you originally meet Dean Domino, head downstairs and exit through the south door, then head to the south wall directly opposite. The lover's mark is on the pillar in the south west corner.
 * Residential District: Go up the stairs directly across from the entrance from the Villa, go through the house on your right, then head up the stairs you see as soon as you exit. Once inside the house look for an oven to the left. The lover's mark is on the left side of the oven itself along with a first aid box beside it.
 * Salida del Sol North: From the apartment exit in the wall, turn right and follow the path until it makes a right turn; instead of following it, turn left and enter the hole in the wall which leads to a shop with a hologram. Exit the shop's other entrance and turn right until you reach a wall that says "Where Are We". Turn to the right and follow the stairs, passing the courtyard, then follow the archway and keep to the right so you enter another courtyard. The lover's mark is diametrically opposite of where you enter the courtyard behind a pillar.
 * Salida del Sol North: Locate the snow globe. Exit that room, head west and around the narrow roof edge, through the poison fog, then across the top of the gate arch to the opposite roof edge, finally turn left and go to the north wall. There the Courier will find a lover's mark and a weapon repair kit.
 * Villa, east side: Face the doors to Salida del Sol South, turn north-west and walk under the arches; at the back wall the Courier will find a lover's mark and food items.
 * Villa, east side: Having the doors to Salida del Sol South behind you, look up to the left and on a wall connecting two buildings a lover's mark can be seen. Jump up and grab a box on a plank between the two roofs.
 * Villa, west side: From the Villa's east side hologram control terminal 01 go south east, up the stairs and follow the left wall. Under the first arch the Courier finds a lover's mark and a metal box that contains a sensor module and 4 or more Sierra Madre chips.

Appearances
Hollowed-out rocks appear commonly in Fallout: New Vegas, while the lover's mark stashes appear only in Dead Money.