The Tisza (also known as Tysa or Theiss) is one of the major rivers located in Central and Eastern Europe. It is historically significant for its geographical reach, having once been referred to as "the most Hungarian river" because it flowed entirely within the territory of the Kingdom of Hungary.
In the modern era, the river's course crosses several different national borders. While it remains a primary waterway in the region, its jurisdiction now extends across multiple countries rather than being contained within a single nation.