Sixth Regiment of the Infantry Duke Margis of Pilėnai in the Guard of the Demarcation Line (1920–192

1919 June 15 The 1st Battalion of the Second Infantry Regiment was separated from the regiment and named the Separate Marijampolė Battalion. November 20 the battalion was transformed into the Sixth Infantry Regiment on 5 November. who received the name of the Duke of Pilėnai Margis.
1920 The Sixth Regiment took part in a confrontation with the Polish army, fighting a "rebellious" Polish gen. mjr. A group led by Lucian Zheligovsky. November 29 In Kaunas, the representatives of Lithuania and Poland signed a ceasefire agreement ending the Lithuanian war on independence and the establishment of a 6 km neutral zone between the two countries.
1920 December 12 The Sixth Regiment was ordered to guard the bar from Jakėnai to the eastern shore of Lake Ilgis (?). December 27 The "margiečiai" received an order to leave the guarded bar for the Ninth Regiment. The 1st Battalion of the Sixth Regiment was transferred to Verbyliškės district, the 2nd to Doškoniai village district, and the 3rd to Jieznas. 1922 November 1 according to the data, the regiment guarded a 40 km long stretch of neutral line, building 29 guards.
With the partial protection of the demarcation line, the military leadership had to deal with many pressing issues. One of them was related to the fact that after the end of active military action, some soldiers began to lose vigilance, so the soldiers' letters to the household contained detailed information about the military parts, their deployment locations, and marches. The issue of the food security of the flock was also important: in 1922. May 1 a partial Farm Company was formed, whose soldiers were obliged to grow vegetables and other crops on a specially leased plot of land. Efforts were also made to pay more attention to the education and training of soldiers, to conduct inspections and maneuvers, and to simulate military actions in the conditions of enemy invasion. In addition, the problem of order and discipline was topical and painful: in 1921. December 12 Due to the financial and other disorder in the regiment, Lieutenant Colonel Jurgis Butkus was removed from the command of the army by the order of the army leadership, and later a criminal case was instituted against him.
The Sixth Regiment had to take part in 1923. in battles over the Valkininkai-Rūdiškės railway section. Just before the Polish attack, the neutral zone was guarded by the 2nd Battalion of the Regiment (one company needed to guard a bar about 10 km wide and there was no solid front). The attack on Polish forces began on February 14. The offenders initially occupied several villages in the partially protected section, but until 18 February. The Sixth Regiment was able to fully recover the positions it had before the Polish invasion. After the withdrawal of the Poles, one of the battalions of the Sixth Regiment continued to guard the section of the demarcation line from Jakėnai to Daugirdiškės. 1923 In the spring, the regiment was moved to a new permanent location - Alytus.