Ślęza is a 78.6 km long river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 in Lower Silesia

Lower Silesia

Lower Silesia ; is the northwestern part of the historical and geographical region of Silesia; Upper Silesia is to the southeast.Throughout its history Lower Silesia has been under the control of the medieval Kingdom of Poland, the Kingdom of Bohemia and the Austrian Habsburg Monarchy from 1526...

, southern Poland

Poland

Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

, a left tributary of the Oder

Oder

The Oder is a river in Central Europe. It rises in the Czech Republic and flows through western Poland, later forming of the border between Poland and Germany, part of the Oder-Neisse line...

. It starts in the Niemcza Hills (Wzgórza Niemczańskie), part of the Sudete Highlands (Przedgórze Sudeckie), and flows near Mount Ślęża

Mount Sleza

Ślęża is a mountain in the Sudetes foothills in Lower Silesia, from Wrocław, southern Poland. This natural reserve built mostly of granite is 718 m high and covered with forests....

 through the Silesian Lowland (Nizinia Śląska) and enters the Oder in Wrocław.

The most important tributary is: Mała Ślęza ("Small Ślęza"). The most important towns on the river are: Niemcza

Niemcza

Niemcza is a town in Dzierżoniów County, Lower Silesian Voivodeship, in south-western Poland. It is the seat of the administrative district called Gmina Niemcza....

, Tyniec nad Ślęzą

Tyniec nad Sleza

Tyniec nad Ślęzą is a village in the Administrative District of Gmina Kobierzyce, within Wrocław County, Lower Silesian Voivodeship, in south-western Poland. Prior to 1945 it was in Germany.It lies approximately south of the regional capital Wrocław....

, Jordanów Śląski

Jordanów Slaski

Jordanów Śląski is a village in Wrocław County, Lower Silesian Voivodeship, in south-western Poland. It is the seat of the administrative district called Gmina Jordanów Śląski. Prior to 1945 it was in Germany....

 and Wrocław.

The name probably is derived from a Silesian word meaning "wet swampy place". In a papal bull

Papal bull

A Papal bull is a particular type of letters patent or charter issued by a Pope of the Catholic Church. It is named after the bulla that was appended to the end in order to authenticate it....

 from Hadrian IV in 1155 the river is called the Selenza.

The names of the Ślęza and Mount Ślęża are both of Silesian origin, although the Ślęza is spelled with a standard Z

Z

Z is the twenty-sixth and final letter of the basic modern Latin alphabet.-Name and pronunciation:In most dialects of English, the letter's name is zed , reflecting its derivation from the Greek zeta but in American English, its name is zee , deriving from a late 17th century English dialectal...

 and Mount Ślęża is spelled with a Ż diacritic

Dot (diacritic)

When used as a diacritic mark, the term dot is usually reserved for the Interpunct , or to the glyphs 'combining dot above' and 'combining dot below'...

- English zh.