Just to supplement Wlodek Matuszewski posting on Wisztyniec, the following data is extracted from the Kingdom of Poland Geographical Dictionary (Słownik Geograficzny Królewstwa Polskiego) and few other sources.
Town Wisztyniec was established in 1538, city rights were granted by the Grand Duke of Lithuania in1 570, and Jewish people have been given rights to establish synagogue and cemetery on January 1,1589.
Beginning in the 1850s, a significant number of the town's Jews emigrated to Germany, the United States, and South Africa
At the end of 19th century, (I believe statistics are refer to the year 1876), in town were counted nine (9) Eastern Orthodox, 1,778 Protestants and 2,453 Jewish residents.
During the Holocaust, all of Vištytis' Jews were murdered, mainly by local collaborators in the town. The exact number murdered is unclear; estimates range from 200 - 400 Jews (out of the town's general population of around 1000). First the men were shot, then the women - but, to save bullets, the Jewish children were killed by having their heads bashed against the trees in the town park. A memorial to the victims was later erected by the Soviets near a windmill called Grist Mill, but the plaque made no mention that those buried in the nearby fields were Jews. Later, a 'Jewish' tombstone was erected that clearly noted what happened.
(2) Yad Vashem, Pinkas Hakehillot, Encyclopedia of Jewish Communities from their foundation till after the Holocaust: Lithuania (1996) pp.260–262
MASS MURDER OF THE JEWS FROM VIŠTYTIS
Holocaust Atlas of Lithuania