The Dacian fortress of Costești is situated on Dealul Cetăţuia ("Stronghold Hill"), at the 561 m altitude, on the left bank of the Apa Grădiştii at the point where the valley is narrowing. Even if it is not the highest point in the area, the hill dominates the landscape offering a good visibility over the Mureș Valley to the north.
The fortress had a complex system of fortifications and different facilities. Many of them are still visible today, going through a process of primary conservation. The fortress occupies the upper part of the hill; the hill top was levelled by the Dacians, resulting a ellipsoidal plateau 160 m long and 20-25 m wide. On the slopes several terraces were built, some of them being outside the fortified area. The civil settlement probably occupied the lower terraces as well as the lowland near the valley, under the present centre of the village.