Островский район
The district lies in the basin of the Velikaya River and thus of the Narva River. The most significant rivers in the district are the Sinyaya and the Lzha, both originating in Latvia. The Sinyaya, a tributary of the Velikaya, crosses the district from south to north. In particular, the settlement of Krasnogorodsk is located on the banks of the Sinyaya. The Lzha, a tributary of the Utroya, forms a stretch of the state border between Russia and Latvia and proceeds to form the border between Krasnogorodsky and Pytalovsky Districts. A number of lakes are located in the district. The biggest ones are Lakes Velye (shared with Ostrovsky District), Pitel (shared with Latvia), and Vysokoye.