Kushk-e Khaleseh-ye Pain (Persian: كوشك خالصه پائين‎, also Romanized as Kūshk-e Khāleşeh-ye Pā’īn; also known as Kūshk-e Pā’īn) is a village in Lajran Rural District, in the Central District of Garmsar County, Semnan Province, Iran.