The Russo-Turkish frontier from Cram's 1896 Railway Map of the Turkish Empire. The Black Sea is in the northwest, Persia to the southeast. The area had a large Armenian and Christian population, and was a principal site of the Armenian Genocide and of Russian military successes.

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The Caucasus Mountains stretch between the Black and Caspian Seas in Russia and along its border with Turkey. In 2015 the region also includes the countries of Georgia, Armenia, and Azerbaijan. At 18,481 ft., Mt. Elbrus is the highest mountain.

In the 1878 Treaty of Berlin ending the Russo-Turkish War, Turkey lost territory to Russia in the Caucasus.

In 1914, the frontier zone had a significant Christian population, much of it Armenian. Each empire had a primary fortress in the region, Kars in Russia, Erzerum in Turkey. The two countries clashed in indecisive battles along the border in November and December, 1914. Each side gained and gave ground and lost about 7,000 men until winter set in and fighting stopped.

Turkish War Minister Ismail Enver Pasha launched a winter offensive against Russia in the region in late 1914. His invasion force had to cross the country, and was ill-prepared, ill-trained, and ill-supplied for a winter war in the mountains. In the Battle of Sarikamish from December until mid-January, 1915, Enver destroyed one of his armies.

Caucasus Mountains is a mountain range in Europe.