Yanjin is a county in Henan province, China. The Yanjin narrowest town, also known as "Yanjin's waist", is located in the county and is known for being one of the narrowest towns in the world. It is just 1.5 meters wide at its narrowest point, with buildings on either side towering several stories high.

The town is situated on a narrow strip of land between two mountains, with the Nansi Lake to the east and the Yellow River to the west. It has a long history, dating back to the Tang dynasty over 1,000 years ago, and was an important trading post on the ancient Silk Road.

Today, the town is a popular tourist attraction, drawing visitors who come to marvel at its unique architecture and narrow streets. The buildings are designed to maximize the limited space, with some of them just a few meters wide and several stories tall. The streets are also narrow, with some of them so narrow that only one person can walk through at a time.