The The Küçük Menderes Valley takes its name from the Küçük Menderes River, which originates in the Kiraz district of İzmir and reaches the Aegean Sea on the Pamucak coast of the Selçuk district of İzmir. The ancient name of the river is Kaystros. Similar to other river valleys in Western Anatolia (Büyük Menderes-Maiandros, Gediz-Hermos, Bakırçay-Kaikos), it is a highly productive region in terms of agriculture. In the valley extending in the east-west direction, besides the fertile plain for agriculture, there are road networks that end in the Aegean Sea and contribute significantly to the economy of the settlements. These advantages, which were vital for an ancient society, enabled the region to be opened to settlement from early times. Küçük Menderes River is the source of life for many ancient settlements established in the valley. Many water sources, large and small, that reach the main source with the side branches, offer great opportunities for the agricultural produc- tion of the region. The fertile plain and abundant water resources revived the economies of the ancient settlements in the region. The water resources in the valley meet the drinking water needs of settlements such as Ephesos and Hypaipa, which stand out with their crowded urban popula- tions. Archaeological research and epigraphic data have shown that a waterway reaching Ephesos originated in Küçük Menderes. In the ancient world, water structures were an important element in the city and the countryside. Water structures, which are built beyond a need to sustain daily life, also function as a propaganda tool for the governments. Aqueducts, large-capacity baths, bridges, monumental fountains are built. In this study, the effect of the river on ancient settlements was dis- cussed. The advantages offered by the valley to rural settlements with its abundant water resources and fertile agricultural lands were conveyed. It is understood that the rural settlements are on the rise of the society with agricultural production and they have the bath structures built. Two bath structures that can be dated to the Roman Imperial-Late Antiquity, which were identified during the field surveys carried out in the region between 2019-2022, are introduced. One of these baths was identified in the Ödemiş Pirinççi neighborhood. There is a high probability that the remains in Pirinççi are balneum. Another bath was discovered in Kiraz Kaleköy.