The Battle of Czarnowo was fought on 23–24 December 1806 during the War of the Fourth Coalition, part of the Napoleonic Wars. French soldiers under the command of Marshal Louis-Nicolas Davout forced a crossing of the Wkra near Pomiechowo. When they advanced eastward to Czarnowo they were fiercely resisted by Russian troops led by Lieutenant General Alexander Ivanovich Ostermann-Tolstoy in an all-night contest. In the early morning hours of the 24th, Ostermann-Tolstoy ordered a retreat. The fighting caused about 1,400 casualties on each side.