Springing forth from between the Hsuehshan and Central Mountain Ranges and winding its way across the Lanyang Plain is the Lanyang River. As the first place along the course of the river, Sanhsing benefits greatly from its as yet unpolluted waters-waters which make the land fertile, and the river itself helps nurture the cultured feel of the village.
發源於雪山山脈和中央山脈之間的蘭陽溪，在進入了三星之後逐漸平緩，貫穿遼闊的蘭陽平原，做為平原上首先受到河水滋潤的三星，水質未受工業污染，農作肥美，也滋養了此地的人文風采。