The genus Syringa L. comprises 12 species worldwide and about 2,500 horticultural cultivars, indicating its high ornamental value. Syringa oblata var. dilatata has been known from North Korea and northern China, with no previous records from central or southern Korea. In this study, we report for the first time a population of S. oblata var. dilatata from central-southern Korea and describe its habitat characteristics and population structure. The habitat was located on a limestone slope with an east-northeast aspect and an inclination of 5-32 degrees, where calciphilous species were observed in the herb layer. The population consisted of 97 mature individuals over 1 m in height and 1,057 individuals in total, including juveniles. Flower color variation was also observed, with 50 purple-flowered and 15 white-flowered individuals. The population exhibited a stable inverse J-shaped structure, suggesting continuous recruitment and persistence. Although no immediate threats were detected, trampling and anthropogenic disturbance should be considered if site information becomes public. Based on the currently available data, this taxon was assessed as Critically Endangered (CR) under the National Red List criteria B1B2a(i,ii,iii).