Contrary to what the in-game hints would have you believe, there are actually 51 Silver Keys scattered throughout Fable II. Since they don't get used up when you open a chest with them, you only actually need to track down 20 in order to open all but the very last chest (which only has 50,000 gold in it, anyway). If you're going for The Hoarder achievement, though, then this list should help you complete your goal:

	Bandit Coast Silver Key #1 Entering the Bandit Coast from Brightwood, walk down the path until just before it makes a nearly 180 degree turn. You'll spot this key sitting on a small landing to your left.
	Bloodstone Silver Key #1 As soon as you enter the Bloodstone area from Wraithmarsh, go into the tomb on your right. Perform whatever expression the statue inside is looking for and he'll open the door to a tomb a little further down the path containing the silver key.
	Bloodstone Silver Key #2 Enter the cellar to the right of Bloodstone's furniture shop, then kick the floating target to open the door leading to the silver key.
	Bloodstone Silver Key #3 Proceed to the far end of the waterfront and take a plunge into the water next to the crane. The dive spot there contains a silver key.
	Bloodstone Silver Key #4 While visiting Lion's Head Isle during the Treasure Island of Doom! quest, you can grab a silver key from the ledge off to your right when you reach the central area of the island.
	Bloodstone Silver Key #5 You'll be able to see this key shortly after entering The Sinkhole, but you won't be able to gain access to it until you've raised the water level using the lever in Captain Dread's chest.
	Bower Lake Silver Key #1 This will no doubt be your very first silver key. It's located on the right side of the Guild Cave/Bower Lake Tomb entrance.
	Bower Lake Silver Key #2 During a return visit to the Gypsy Camp, you can pass through a new opening in the fence surrounding the camp. Make your way to the top of the southeast tower to find this key.
	Bower Lake Silver Key #3 This silver key is nestled behind a tree to the southeast of the Tomb of Heroes entrance.
	Bower Lake Silver Key #4 You'll be paying a visit to the Tomb of Heroes during the Rescue Charlie quest. When you finally reach the room where Charlie's busy fighting Hollow Men, check behind the stone pillars to your right.
	Bowerstone Cemetery Silver Key #1 This silver key is simply sitting in front of some tombs near the top of the southern hill.
	Bowerstone Cemetery Silver Key #2 Check inside the small shed next to Mickey, the guy who gives the Civilian Displacement quest.
	Bowerstone Cemetery Silver Key #3 Search the back room on the second floor of the Bowerstone Cemetery Mansion for this silver key.
	Bowerstone Cemetery Silver Key #4 After you've purchased the Bowerstone Cemetery Mansion and entered Shelley Crypt, you can smash through a wall near the crypt's exit to locate a secret stairway leading to a silver key.
	Bowerstone Market Silver Key #1 Use the southeast dive spot below the market bridge to reach this secluded room near the Bowerstone Market entrance. A silver key and a chest await you.
	Bowerstone Market Silver Key #2 Let your dog lead you to this silver key in the alley behind the Cow & Corset.
	Bowerstone Market Silver Key #3 Enter the cellar on the lower level of the World of Chairs furniture store, then shoot the target behind you to open the portcullis barring the way to this silver key.
	Bowerstone Old Town Silver Key #1 Descend into the cellar just outside of The Helping Hand to score this silver key.
	Bowerstone Old Town Silver Key #2 This particular silver key is underneath the stairway on the ground floor of the Old Town Warehouse.
	Bowerstone Old Town Silver Key #3 Step out on the balcony in The Invisible Hand residence and you'll have yourself another silver key.
	Brightwood Silver Key #1 A silver key taunts you from one side of the collapsed bridge in the southwest corner of the map.
	Brightwood Silver Key #2 This recessed area can be accessed through the bandit camp in the southeast corner of the map, just on the west side of the river.
	Brightwood Silver Key #3 The path in the northeast corner of the map will take you to a landing with a pair of large statues. The silver key sits between them.
	Brightwood Silver Key #4 After you've purchased the Giles Farm, you'll receive a key granting you access to the Farm Cellar. You'll stumble upon this silver key within.
	Brightwood Silver Key #5 Late in the game, you can ascend to the second floor of the Brightwood Tower and vault from the ledge near the cullis gate to reach Archon's Knot. This silver key can be claimed during the second spike puzzle.
	Fairfax Gardens Silver Key #1 Go underneath the stairway leading to the entrance of Castle Fairfax and you'll discover this key sitting in the tunnel.
	Fairfax Gardens Silver Key #2 During the Love Hurts quest, you'll enter Lady Grey's Tomb for a chance at nabbing this silver key sitting in the sand.
	Guild Cave Silver Key #1 After taking a plunge into the water below and fighting a wave of beetles, you'll discover this silver key in the first main room.
	Oakfield Silver Key #1 Manure Manor might be a one-star abode, but at least it houses this silver key.
	Oakfield Silver Key #2 It would be pretty difficult to miss this silver key on your way to the Temple of Light.
	Oakfield Silver Key #3 This silver key is sitting off to your right in one of Echo Mine's first rooms.
	Oakfield Silver Key #4 This silver key is sitting at the top of the stairs inside the Porridge Cottage.
	Oakfield Silver Key #5 While escorting Hammer in The Wellspring Cave, you'll discover this silver key behind the platform in the first water-filling room.
	Oakfield Silver Key #6 After Hammer buries her father, you can score this key sitting next to some bails of hay.
	Rookridge Silver Key #1 A silver key rests behind the statue on the small landing where the Till Death Do Us Part quest can be accepted.
	Rookridge Silver Key #2 Exiting the Rookridge Inn on the second floor, you'll find a silver key a little ways ahead sitting at the end of the mining cart track.
	Rookridge Silver Key #3 This hard-to-find key is buried amid some mushrooms just before the final waves of Hobbes in Hobbe Cave. A well-trained dog can sniff it out.
	Rookridge Silver Key #4 When you emerge from Hobbe Cave victorious, go around to the back of the building you're in. A silver key rests on the outer deck.
	Rookridge Silver Key #5 Swim through the water past Hobbe Cave to reach Gemstone Grotto, where this silver key can be nabbed.
	Rookridge Silver Key #6 Once you've gained entrance to the Temple of Shadows, proceed to its basement and go into the main council chambers. This key sits behind the central chair.
	Westcliff Silver Key #1 Westcliff's first silver key sits in a small shack at the southern camp (with the watchtower and silver chest).
	Westcliff Silver Key #2 This one's on a small landing that can only be reached while swimming in the water below the bridge. The landing is due east from Old Tin Mine.
	Westcliff Silver Key #3 Just before exiting the Howling Halls, you can grab this silver key in the small candlelit area on the opposite side of the room.
	Westcliff Silver Key #4 Head to the beach below the Westcliff Camp and you'll find this silver key behind some crates.
	Wraithmarsh Silver Key #1 When you reach the Drowned Farm, check the second floor of the first house on your left for this key.
	Wraithmarsh Silver Key #2 When you reach the ring of tombs in the southwest corner of the map, check the first tomb off to your left for another silver key.
	Wraithmarsh Silver Key #3 There's a small shack sitting amid some water on the western area of the map. Take the little fenced-in path behind it to reach this key.
	Wraithmarsh Silver Key #4 You'll discover this key behind a smashable wall during your visit to Shadow Court for Reaver.
	Wraithmarsh Silver Key #5 Once you've gained entrance to Twinblade's Tomb via the Love Hurts quest, slide open the final tomb itself to uncover a silver key.
	Wraithmarsh Silver Key #6 A few paces away from #5 is another silver key lying next to the sarcophagus you'll be opening for the Love Hurts quest.
	Wraithmarsh Silver Key #7 Upon exiting Twinblade's Tomb, there will be another silver key waiting to be plundered.