It is a village in the Argentinean province of Catamarca, about 24 km from Fiambalá. As its name suggests, it is located at the foot of gigantic sand dunes.
It has a main square and a church. There is a big cross on the top, where you can climb up and enjoy a panoramic view of the populated area and the mountains with dunes.
On one side of the village is the Fiambalá River, which at certain times of the year is dry and covered with sand. On the other side of the river (there are streets crossing it) there is another area populated with vineyards, as the terrain is suitable for this activity. There is a main street running the length of this area. At the end of this street heading south there is a sandy road or track that leads to the sand dunes, although my recommendation is not to try to go with a regular car because it is easy to bury the vehicle.
To get to Medanitos from Fiambalá, first take Provincial Route 34 towards the north. After passing the village of Saujil, a secondary road opens up on the right that leads to the village. Nowadays the whole route is paved.