The Ponary massacre (Polish: zbrodnia w Ponarach), or the Paneriai massacre (Lithuanian: Panerių žudynės), was the mass murder of up to 100,000 people, mostly Jews, Poles, and Russians, by German SD and SS and the Lithuanian Ypatingasis būrys killing squads,[3][4][5] during World War II and the Holocaust in the Generalbezirk Litauen of Reichskommissariat Ostland.

[3][11] Lithuania became one of the first locations outside occupied Poland in World War II where the Nazis mass-murdered Jews as part of the Final Solution.

[15][16] Following Żeligowski's Mutiny and the creation of the short-lived Central Lithuania, in accordance with international agreements ratified in 1923 by the League of Nations,[17] the town of Ponary became part of the Wilno Voivodship (Kresy region) of the Second Polish Republic.

Yitzhak Arad supplied information in his book Ghetto in Flames based on original Jewish documentation augmented by the Einsatzgruppen reports, ration cards and work permits.

[21]: 215  The reason for such a wide range of estimated deaths was the presence of war refugees arriving from German-occupied western Poland, whose residence rights were denied by the new Lithuanian administration.

On the eve of the Soviet annexation of Lithuania in June 1940, Vilna was home to around 100,000 newcomers, including 85,000 Poles, and 10,000 Jews according to Lithuanian Red Cross.

Information about the massacre began to spread as early as 1943, due to the activities and works of Helena Pasierbska, Józef Mackiewicz, Kazimierz Sakowicz and others.

The first monument on the site was built by Vilnius Jews in 1948 but was replaced by the Soviet regime with a conventional obelisk dedicated to "Victims of Fascism".

The massacre was recorded by Polish journalist Kazimierz Sakowicz (1899-1944) in a series of journal entries written in hiding at his farm house in Wilno, Lithuania.

After Sakowicz's death in 1944, the collection of entries were located and found on various scrap pieces of paper, soda bottles and a calendar from 1941 by holocaust-survivor and author Rahel Margolis.

The diary became important to tracing the timeline of the massacre, and in many instances gave closure to surviving family members on what happened to their loved ones.