Just outside the western boundary of the national park area, another mountain Gyebangsan rises to 1,577 m (5,174 ft), higher than conventional Odae-san's summit, and they are connected by a 10 km long ridge; it is controversial whether or not to include this within the cluster or consider it as separate.

[1] Odae-san has been a highly sacred mountain-cluster of Korean Buddhism ever since Master Jajang founded Woljeongsa Temple in its main valley and interred purported relics of Sakyamuni Gautama Buddha halfway up the southern slope of the Biro-bong Summit in 643 CE, after determining that it was geographically similar to China's Wutaishan and therefore also a doryang "residence" for Manjushri the Bodhisattva of Wisdom (Munsu-bosal in Korean).

[2] One of the four mountain-based (for protection) royal archive buildings of the Joseon is located near the center of the Odae-san cluster, just north of Woljeong-sa, reconstructed near the end of 20th century.

[5][6] In a remote part of Odae-san, three peat high-moor fens (a rarity in Korea) in an area of just 2300 m2 were designated as the Odaesan National Park Wetlands under the international Ramsar Convention, on October 13, 2008.

The central areas of the Odae-san mountain-cluster are preserved as the Odaesan National Park, famous for hiking, tourism, pilgrimage and public recreation, especially in October when the leaves of its many deciduous trees turn red, gold and yellow.

It contains two of Korea's most prominent Buddhist monasteries, Woljeongsa in the south of the main valley (at the entrance to the park)[8]) and Sangwonsa at its northern terminus, as well as a half-dozen major hermitages (subsidiary temples), all members the Jogye Order of Korean Buddhism.

[10] The northeast arm of the national park begins at Noinbong (노인봉; 老人峰) "Elderly Person [Grandfather] Peak"), and soars 1,338 m (4,390 ft) above Highway 6.

From Noinbong flows the long, beautiful waterfall-gorge Sogeumgang Valley (소금강계곡; 小金剛溪谷) or "Minor Diamond Scenic-Gorge" to the northeast until exiting at the northern tip of Gangneung City.