Chełmno land (Polish: ziemia chełmińska, German: Kulmerland ) is a historical region, located in central-northern Poland.
Chełmno land is named after the city of Chełmno (historically also known as Kulm). The largest city in the region is Toruń; another bigger city is Grudziądz.
It is part of historical Prussia, and according to many, also of Pomerania; it is currently within of the Kuyavian-Pomeranian Voivodship.
It is located on the right bank of the Vistula river (which is its western border), from the mouth of the Drwęca (southern boundary) to the Osa (northern). Its eastern frontier is Lubawa Land.
The first historical account of Chełmno and Chełmno Land dates back to 1065 when Bolesław II of Poland granted a tax privilege to an abbey in a nearby Mogilno. The document lists Chełmno ("Culmine") along with other towns which then belonged to the province of Masovia. The area, being closest to the Polans, came to be populated by the Lechitic Kuyavians and tribes from Greater Poland. The Masovians were led by Masos, who left the Polish duke Boleslaw I and sought refuge with the Prussians. When this area was subdued by the rulers of the Polans Chełmno became a local centre of administration (kasztelania). Chełmno Land was Christianised in the 11th century.