Yilan City is located in the center of the Lanyang Plain in northeastern Taiwan and serves as the administrative seat of Yilan County. It is also the most populous city within the county. Covering an area of approximately 29.4 square kilometers, it is the smallest county-administered city in Taiwan by area. However, its geographical location and historical background grant it significant importance in political, economic, and cultural development.
Historically known as "Wu-Wei," Yilan City began its rapid development after being incorporated into the Qing Empire in 1810. In 1812, an administrative office was established, and the following year, the construction of Yilan City began, gradually becoming the administrative and cultural center of the Lanyang Plain. Through urban development during the Japanese colonial period and administrative restructuring after World War II, Yilan City has remained the core area of Yilan County. Today, it houses key county-level institutions such as the County Government, County Council, and County History Museum, and is considered the cultural and educational hub of Yilan.
Geographically, Yilan City lies on part of the Lanyang River alluvial fan and belongs to the coastal plain geological zone. The strata mainly consist of sand, gravel, and clay, forming Holocene alluvium. The terrain is flat, and the soil is fertile—ideal for both agriculture and urban development. The city is bordered by neighboring townships: Zhuangwei to the east, Wujie to the south, Yuanshan to the west, and Jiaoxi to the north. It enjoys convenient transportation and well-developed external connections.
In terms of climate, Yilan City features a subtropical oceanic monsoon climate, characterized by warm and humid conditions year-round. The average annual temperature is around 22.2°C. July is the hottest month, with temperatures reaching approximately 28°C, while January is the coldest, yet still remains above 15°C. There are about 210 rainy days per year, with an average annual rainfall of around 2,776 millimeters. Rainfall is unevenly distributed, with the main rainy season occurring from May to September, including rainfall from plum rains and typhoons. September marks the peak of precipitation. The high humidity and abundant rainfall create Yilan City's lush and verdant natural environment.
Blending rich historical and cultural heritage with geographical advantages, Yilan City not only serves as the administrative center of Yilan County but also as the core of its cultural, educational, and everyday life, showcasing a unique character that harmoniously merges tradition and modernity.
