Abastumani is a small town (daba) and climatic spa in Adigeni Municipality in Samtskhe-Javakheti region. It is located on the southern slopes of the Meskheti Range (Lesser Caucasus), in the small river valley of Otskhe, 25 km northeast of Adigeni and 28 km west of Akhaltsikhe. As of the 2014 census, it had a population of 937. The Georgian National Astrophysical Observatory is located at Abastumani.
In medieval Georgia, the area of modern-day Abastumani was part of the district of Odzrkhe so named after a fortress whose ruins survive near the townlet. In the 16th century, it fell to the Ottoman Empire under whose rule the area was deserted, but its hot springs were appreciated and frequented by locals. Under the Russian rule, a short-lived German colony of Friedenthal (Russian: Фрейденталь) emerged there in 1842. In the 1850s, it was recolonized by the Russians under the patronage of Viceroy of the Caucasus Mikhail Vorontsov. The new settlement acquired the name Abbas-Tuman after a nearby located village and became popular for its climate and thermal waters. Its development as a resort is chiefly associated with Grand Duke George Alexandrovich (1871–1899), a member of the Russian imperial family, who had retired there due to his ill-health. Abastumani acquired the status of an urban-type settlement (Georgian: daba) under the Soviet Union in 1926.nTourism infrastructure has been renovated since the mid-2000s.
Abastumani possesses a moderately dry mountainous climate, with relative humidity reaching 50% only in summer. The annual average number of hours of sunlight is 3,000. Average annual precipitation is 626 mm. Average annual temperature is 6.4 to 6.5 °C (44 to 44 °F) in January and 17.2 °C (63 °F) in July. Abastumani’s three hyperthermic springs (39-48.5 °C) are little mineralized, rich in sulfate-sodium chloride waters. They have long been used in the treatment of tuberculosis. Abastumani is also a starting point for hikes into the Borjomi-Kharagauli National Park.