The János Arany Museum was established by the Mayor Kázmér Dezső 75 years ago. It is a county museum showing significant ethnographic, archaeological, history and fine art reclics. It is the only museum related to János Arany.

The title of the permanent exhibition is a quotation from a poem by János Arany: „Hey, Nagykörös, famous town...” The section dealing with the history of the town includes the development of the market town, the part about the Danube-Tisza Interfluve includes a gilded sword, a gilded bronze procession cross from the 13th century Ludas, late Gothic stove tiles, guild records, wrought iron works from the 17, 18, 19th centuries.

The War of Independence of 1848-49 is represented by a rich collection of objects. The Arany Memorial Exhibition evoking the heydays of the market town is an outstanding part of the showing including documents from the Reformed Church School and manuscripts by János Arany. There is also a section on historic events of the 20th century, garden culture and food industry. The folk art section is entitled Headstones from the Danube-Tisza Interfluve. The Pest County School History Exhibition opened at a building of the Reformed Church School at 1 Helmeczi Street. The exhibition presents the history of the school from 1949 to the nationalisation. It is divided into two larger sections. The first one presents methods of education with an old blackboard, exercise books and study books in showcases. The map of the county shows every habitat including the school types.

The other unit is interior-like. School desks made at the Kühne Factory that was famous of manufacturing agricultural machines are from the first part of the century. The alphabet and maps hung on the walls. Scale models, models of various machines, minerals and stones are displayed in the showcases.