The village stretches along the Velika Maskova stream, which originates from springs near Mount Zruby (Malyi Verkh). Nearby are the peaks of Kytvan and Klyva. From here, you can see neighboring villages: Lukva (Pryslyp), Solotvyn, Kryvets, Rakovets, Porohy, Dzvynyach, Zhuraky, Monastyrchany, and Rosilna.
Kosmach includes the hamlets of Sadzhivky, Kosmachivka, and Rakiv Potik, as well as the informal districts of Pohari and Luhy.
The first recorded mention of the village dates back to 1785–1788. Kosmach grew from the hamlet of Kosmachivka.
In the past, the main street ran from the forest in the west to the river and the Hrebli road, which connected Rosilna to Solotvyn. Until the 1970s, the only named street was Maryna Street, named after a woman who saved the village by diverting the Tatars in another direction, though she lost her life. People used to live on both sides of the river and carried water directly from it, as wells were almost nonexistent.
