Xiaoyoukeng in Yangmingshan National Park is a large volcanic steam vent area with hiking trails, fumaroles, sulfur deposits, and natural hot springs. Even though the name means "small sulfur hole," it is perhaps the largest and most easily accessible volcanic steam vent area in Taiwan. One could say that it is the Yellowstone of Taiwan. It is a quiet a pleasant stop on the mountain and worth a visit on your trip to Yangmingshan.

The area known as Yangmingshan now was formed by volcanoes about 700,000 years ago, forming many mountains about 1000 meters or less in northwestern Taiwan. The park still features active volcanoes, vents, and hot springs.

The original name of the area was Caoshan (grass mountain 草山). During the Qing Dynasty, the area was used to harvest sulfur, and many of the hills were burned to help catch sulfur thieves.

In 1927 during the Japanese era, Yangmingshan was made as the first national park in Taiwan, then known as Datunshan National Park Association.

In 1950 after the ROC took Taiwan Chiang Kai-shek renamed the park after the philosopher Wang Yangming, and called the area Yangmingshan.

In 1985, after resolving many land disputes, Yangmingshan National Park was officially designated as a national park in the ROC era.

Xiaouyoukeng (literally "Small Oil Crater" gets its name because the there are two main sulfur vents on Yangmingshan, and it was thought to be the smaller one. The venting crater lies about 805 meters above sea level. A few kilometers under the ground, there is a leftover lava chamber from a previous eruption that heats up ground water and sends it spewing back to the surface.

It is a popular stop in Yangmingshan and has two parking lots and visitor's center. It is also one of the starting points for the Mt. Qixing Trail.