Battle of Tannenberg
For the 1410 battle at the same location, see Battle of Grunwald. For the 1944 battle in Estonia, see Battle of Tannenberg Line. Battle of Tannenberg Part of the East Prussian campaign of the Eastern Front in World War I Russian prisoners of war after the Battle of Tannenberg. Date 26–30 August 1914 Location Near Allenstein, East Prussia (today Olsztyn, Poland) 53°29′45″N 20°08′4″E / 53.49583°N 20.13444°E / 53.49583; 20.13444 Coordinates: 53°29′45″N 20°08′4″E / 53.49583°N 20.13444°E / 53.49583; 20.13444 Result Decisive German victory Second Russian Army annihilated Belligerents German Empire Russian Empire Commanders and leaders Paul von Hindenburg Erich Ludendorff Max Hoffmann Alexander Samsonov † Units involved 8th Army 1st Army 2nd Army Strength 150,000 [1] 230,000 [2] Casualties and losses 10,000–15,000 killed or wounded [3] 12,000 killed or wounded [1] Official German data 21–30/08/14: 13,873: [4] 1,726 KIA 7,461 WIA 4,686 MIA 170,000: 78,000 killed or w...