Eylau, Or Eilau, a town of Prussia, province of East Prussia, in the district and 22 m. S. S. E. of the city of Konigsberg; pop. in 1871, 3,723. It is situated on the Pasmar, a small tributary of the Alle, contains an old castle, and has manufactories of cloth, hats, and leather. Here on Feb. 7 and 8, 1807, was fought a battle between the French under Napoleon, 85,000 strong with 350 guns, and the Russians and Prussians, 75,000 strong with 460 guns. The total number of killed and wounded was nearly 40,000, and both sides claimed the victory. In this battle Napoleon was nearly made prisoner, but was saved by his own presence of mind and the heroism of his little body guard of 100 men.-This town is called Preussisch Eylau, to distinguish it from Deutsch Eylau, a small town of West Prussia, in the district of Marienwerder, 70 m. S. S. W. of the former, at the S. extremity of Lake Geserich.