Shards of Mehrunes' Razor

The Shards of Mehrune's Razor can be found in the Cracked Tusk Vaults beneath Cracked Tusk Keep.

Located just East of Falkreath, Cracked Tusk Keep is an Orc Stronghold with very few Orcs guarding it, one in particular named Ghunzul, who holds the key to the Vaults below.