We have often been asked what the oldest tree growing in Lithuania is. It is a difficult question related to the living trees as often they are cut in forests and naturally die off in the parks or are affected by windthrows. However, the longest-grown tree in Lithuania is the oak from our oak wood collection. It is an oak sample with 417 tree rings (sapwood is missing). Although the finding location is not documented, we have two hypotheses: that it is from the timber collection from Klaipėda oldtown/castle or sampled in the peatbog in Lithuania. The cross-section diameter is circa 50 cm, and the average tree ring width is 0.6 mm. Recently, it was dated against Klaipėda oak chronology to 1123–1539.