Wikipedia
Łydynia
Łydyni is a river of north-eastern central Poland, a left tributary of the Wkra at the town of Sochocin, with an overall length of 72 kilometers.
The river flows past Ciechanów and its ancient Mazovian ducal castle. Its own tributaries include the Giedniówka, the Dunajczyk, the Stawnica, and the Pławnica.