page_title: Yilan County, Taiwan
section_title: Geography
hierarchical_section_title: Yilan County, Taiwan / Geography
caption_attribution_description: English: Map of the Taichung (T'ai-chung, Taichū) area, Taiwan (ROC). From the Tawian AMS Topographic Maps series.
context_page_description: Yilan County, alternately spelled I-lan, is a county in northeastern Taiwan, Republic of China.
context_section_description: Yilan County sits on the Yilan Plain, a combined alluvial plain created by Lanyang River and other minor streams with a rough shape of triangle. On the three vertices of the triangle sit the Toucheng, Sanxing and Su-ao Townships with a roughly equal distance of 30 km on the three sides. The Xueshan Range sits on the northwest of Yilan County from Toucheng to Sanxing. The county is geographically divided into the cliffs and the plains. The Central Mountain Range sits to the south from Sanxing to Su'ao.
  The Upper Lanyang River is steep and the rapid current is highly erosive. Large amount of silt carried by the river have little time to settle because of the high slope of the lands where it flows out of the mountains and valleys. An alluvial fan is formed as a result of scattered sand and gravel settling down. Large amount of gravel accumulate in the shallow stream bed, creating alluvial fans that often forms into web-like pattern. The river tends to change courses after floods caused by heavy rainfall or river overflow. The Lanyang River slows down as it reaches mid and downstream where silt begins to settle.
  Yilan County is located in the northeastern Taiwan Island which covers an area of 2,143 km². The longest distance from east to west is 63 km and from north to south is 74 km. From the mountain areas downwards, the land falls in altitude in the stages of mountains, alleys, alluvial plains, lowlands, swamps, sand hills and finally coastline.
  Yilan's Toucheng Township includes Guishan Island and Guiluan Island. The Senkaku Islands, known in Mandarin as the Diaoyu Islands, are claimed as part of the township.
caption: Map including Yilan (labeled as I-lan (Giran) 宜蘭) (1954)
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