"Beyond the Black River" is one of the original short stories about Conan the Cimmerian, written by American author Robert E. Howard and first published in Weird Tales magazine, v. 25, nos.

It's set in the fictional Hyborian Age and concerns Conan's battle against a savage tribe of Picts in the unsettled lands beyond the infamous Black River.

The story takes place in Conajohara, a newly established Aquilonian province recently annexed by King Numedides from the Picts.

Accompanying the young man back to the fort, Conan finds the corpse of a merchant left by a Pictish wizard named Zogar Sag and slain by a swamp demon.

The fort's commander, Valannus, desperately asks Conan to slay Zogar Sag before he raises the Picts against the whole borderlands, especially since Tuscelan is vastly undermanned after Numedides foolishly decided to withdraw most of its garrison.

Conan is able to fend off the pursuing beasts using a symbol he once noticed, and the pair return to the Fort to warn everyone of an impending Pictish assault, but they are too late.

Accompanied by Slasher, he makes his last stand against the coming Pictish raiders, first shooting arrows from concealment and then in a furious face-to-face battle.

He also relates that in the midst of his victory at Tuscelan, Zogar Sag was mysteriously struck dead, sporting the same kind of wounds Conan had inflicted on the swamp demon.