The army was formed on July 15, 1941 in the Moscow Military District. It was ordered to create a defensive line along Ostashkov - Selizharovo - Rzhev. The army was stationed between the 27th Army to the north and the 49th Army to the south. 31st Army was formed with the following units: and on August 1, it was assigned to the Reserve Front, and added the following units: The army was assigned to the Reserve Front on July 30, 1941, and it moved to the defensive line along Ostashkov - Yeltsy - Tishina River. It entered combat on October 2, 1941. At that time, the army was composed of:
Combat operations
1941
The 31st Army engaged the Germans on October 2, 1941, during Operation Typhoon. On October 6, it formed a task force under the command of Major General Polenov, and along with a task force from 19th Army under the command of Lieutenant General I. Boldin, was given the mission to break the enemy advance near Volokolamsk and Rzhev. On October 7 the first snow fell, turning the roads into mud and forcing the 3rd Panzer Group's advance to a halt. The snow allowed the army to set up defensive positions along the Zhuralyovo − Large Yakovtsevo − Ivashkova and create a corridor for retreating Soviet troops. This began the Kalinin Defensive Operation phase of the Moscow Strategic Defensive operations. On October 10, the 110th Tank Division was detached and ordered to Rzhev. On October 19, the army was reduced to: From October 19 to 22, the army fought against German forces, which had broken into the district of Mednoye. The army received reinforcements from the 113th and 252nd Rifle Divisions. On October 22, the army was ordered to take the offensive in conjunction with the 29th and 30th Armies to liberate the city ofKalinin. While unable to retake the city, the attack was able to draw off a number of German forces from the attack on Moscow. On December 5 as part of the Moscow Strategic Offensive, the Kalinin Front began the Kalinin Offensive. Encountering stubborn resistance and repeated counterattacks, the 29th and 31st Army had broken the flanks of the forces defending Kalinin by December 15, and on December 16, the 31st Army liberated the city. On January 7, 1942, troops of the 39th, 29th, 31st and 30th armies were stopped on prepared defensive lines north of Rhzev near Lotoshino.
1942
From January 8 to April 20, the army participated in the Rzhev-Vyazma Strategic Offensive. On April 20, the army moved into defensive positions east of Zubtsov, Russia. On July 23, the army was assigned to the Western Front, and took part in the Rzhev-Sychevka offensive from July 30 to August 23, liberating the city of Zubstov on the 23rd of August. From November 25 to December 20, 1942, the army participated in Operation Mars.
1943
On March 20, 1943, the army crossed the Dnieper River, despite the complications of the spring thaw breaking up the river's ice. The army attempted to goon the offensive, but was unable to break through the German defenses, and by the end of the month the commander decided to discontinue the general offensive and join the defense. Composition as of August 1, 1943: On August 7, the army went on the offensive as part of Operation Suvorov, part of the Smolensk Strategic Offensive. The army made only limited penetrations of the German lines. After a beating of heavy German counterattacks, the attack was suspended on August 11. After a regrouping of the forces, the attack resumed on August 16. However, the forces were unable to advance even a mile and the attack was again suspended on August 20. The attack resumed on August 30 with little progress made. That evening the Germans began to withdraw their forces. The Soviet pursuit began on August 31 with the crossing of the Vopets River. After a week of retreating, the Germans managed to establish a defensive line near Yartsevo and on September 7 took up defensive positions. On September 15 they resumed the attack, crossing the Vop River. In conjunction with the 5th and 68th Armies, they liberated Smolensk on September 25.
1944
From February to March, the army participated in operations to liberate Brest. At the opening of Operation Bagration, the army consisted of: Assigned to the 3rd Belorussian Front, the army Operation Bagration participated in the assault of German forces in the Minsk Offensive encirclement. In addition to the 31st Army, the 2nd Belorussian Front's 33rd, 49th and 50th Armies were given the task of containing the Germans within the encirclement, and defeating German forces in the surrounding area. The elimination of the German forces escaping from the city took place in three phases:
July 5–7 - destruction and suppression of organized attempts to break out. After the surrender of the city, the German forces broke up into several disorganized groups and attempted to escape the encirclement.
July 8–9 - destruction of groups which had taken refuge in the forests south-east of Minsk.
July 10–13 - Soviet troops combed the woods, capturing any remaining small enemy groups.
By the end of the summer of 1944, the forces of the 3rd Belorussian Front and 31st Army had reached the border of East Prussia.
