Kozienice [kɔʑɛˈɲit​͡sɛ] ( listen) (Yiddish: קאזשניץ Kozhnits) is a town in central Poland with 21,500 inhabitants (1995). Located four miles from the Vistula, it is the capital of Kozienice County (Polish Powiat kozienicki). The name of the town first appeared in records in 1429, when it was spelled in Latin Coszinicze (Kozinice). In 1569 it was called Kozienycze – the name comes from the given name Kozina.

Even though Kozienice is part of Lesser Poland, it is situated in the Masovian Voivodeship (since 1999); previously, it was in Radom Voivodeship (1975–1998) and in Kielce Voivodeship (1919–1939, 1945–1975). Near Kozienice, in Świerże Górne, there is a large thermal power station.

History of the town dates back to 1206, when – together with neighboring villages, Kozienice was owned by the Norbertine Nuns from Płock. Subsequently, it used to belong to Polish crown, and remained so until the Partitions of Poland. In 1326 Kozienice was incorporated by King Władysław I the Elbow-high. Located on the ancient road from Kraków to Vilnius and on the edge of the Kozienice Forest, the town became one of favorite retreats of King Jogaila, who founded a church there in 1394. A pontoon bridge was built over the river, which was later moved to Czerwińsk and used by Polish troops to cross the Vistula (Wisła) between June 30 and July 3, 1410 (see Polish–Lithuanian–Teutonic War).

Kozienice County (Polish: powiat kozienicki) is a unit of territorial administration and local government (powiat) in Masovian Voivodeship, east-central Poland. It came into being on January 1, 1999, as a result of the Polish local government reforms passed in 1998. Its administrative seat and only town is Kozienice, which lies 81 kilometres (50 mi) south-east of Warsaw.

The county covers an area of 916.96 square kilometres (354.0 sq mi). As of 2006 its total population is 61,614, out of which the population of Kozienice is 18,541 and the rural population is 43,073.

The county includes part of the protected area called Kozienice Landscape Park.

Kozienice County is bordered by Garwolin County to the north, Ryki County to the east, Puławy County to the south-east, Zwoleń County to the south, Radom County to the south-west, and Białobrzegi County and Grójec County to the west.

The county is subdivided into seven gminas (one urban-rural and six rural). These are listed in the following table, in descending order of population.