|• location||Cernik, Žumberak|
|Length||56 km (35 mi)|
|Basin size||614 km2 (237 sq mi)|
|Progression||Kupa→ Sava→ Danube→ Black Sea|
Kupčina rises in the mountainous areas of Žumberak in the village of Cernik near Sošice, and flows towards the southeast near the eponymous village of Kupčina Žumberačka. It turns slightly to the south, passes near Krašić, and turns back southeast past another eponymous village of Gornja Kupčina, before it enters a wide lowland area near Draganić. It is then partially rerouted into a series of man-made drainage canals before it flows into the Kupa near Donja Kupčina.
- Statistical Yearbook of the Republic of Croatia 2017 (PDF) (in Croatian and English). Zagreb: Croatian Bureau of Statistics. December 2017. p. 47. ISSN 1333-3305. Retrieved 23 May 2018.