A village of 4,100 inhabitants in South-Nyírség, 24 km from Nyíregyháza. A typical main-street settlement. The streets are connected with the main street from the north and south. It was founded by the conquering Balog-Semjén clan in the 11th century. The first part of the present name comes from the name of the settlement called Nagykálló. The oldest monument is the church erected in honour of Saint Michael in 1317. In the 1730s and the 1740s orthodox Romanian shepherds were settled here because a large number of the inhabitants was killed in the plague epidemic. These shepherds rebuilt the church from the Middle Ages in late Baroque style in the 18th century. The 200-year-old Kállay mansion, the residence of the former Prime Minister, Miklós Kállay can be found in the village. The park of the mansion with the line of linden trees has been a nature reserve since 1977. The so-called Lake Mohos of Kállósemjén has been a nature reserve since 1954 with the only sudd in the country.