Ugra River (Oka)
Position of Ugra ( Угра ) in the western basin of the Oka
Ugra (Russian Угра ) is a 339 km long left tributary of the Oka in the European part of Russia.
The Ugra has its source in the Smolensk heights in the southeastern part of the Smolensk Oblast and flows for a distance of 339 km through the Smolensk Oblast and Kaluga Oblast. The catchment area of the river covers an area of 15,700 km ². The amount of water, which leads to the flow varies greatly throughout the year. In the spring, from March to May, the Ugra leads constant flooding from the melting snow and ice. In summer and autumn the river is usually low water, only occasionally interrupted by flash floods due to heavy rains. In winter there is a constant low water. During the spring floods, the water rises over the winter water level by up to 11 meters. During this time the flow amount is about 35 km above the confluence with the Oka an average of 90 cubic meters per second.
The Ugra was since the early Middle Ages, a border river between different kingdoms. Reports on military confrontations on the river date back to the year 1147. The most famous battle is probably standing on the Ugra in 1480th The river at this time was the border between the Grand Duchy of Moscow and the Grand Duchy of Lithuania. In the battle, the army of the Golden Horde under Akhmat Khan and the army of the Grand Duchy of Russia were under Ivan III. opposite. After a short battle, both armies stationed on opposite shores. After the allies of the Mongols, the Grand Duke of Lithuania Casimir IV Jagiello, did not appear and the Russian army could reinforce, pulled the troops of the Golden Horde without a fight back to the south. This battle marks the end of Mongol rule on Russia and the starting point for the ascent of the Russian Empire and the downfall of the empire of the Golden Horde.
During the Patriotic War against Napoleon Bonaparte, the area around Juchnow by partisans to Denis Vasilyevich Davydov was defended. The partisans were so successful that the Napoleonic army, the area not conquered. During the Second World War there were several skirmishes and battles in the area of the river.