The commune is composed of five villages: Cașinu Nou (Kászonújfalu), Iacobeni (Kászonjakabfalva), Imper (colloquially Imper-Doboi or Doboi, Kászonimpér), Plăieșii de Jos, and Plăieșii de Sus (Kászonfeltíz).

The commune lies on the banks of the Cașin River and its tributary, Pârâul Primejdios, in a hilly area at the foot of the Ciuc Mountains.

The villages were part of the Székely Land region of the historical Transylvania province.

After the Hungarian–Romanian War of 1919 and the Treaty of Trianon of 1920, they became part of the Kingdom of Romania and fell within Ciuc County during the interwar period.

At the 2021 census, Plăieșii de Jos had a population of 2,819; of those, 81.2% were Hungarians, 11.56% Roma, and 4.15% Romanians.