The name "Gaya" comes from the Sanskrit for "cow." Gayasan is sometimes called "Someurisan" (head of cow mountain) because (why else?) the mountains are shaped like a cow's head. Consisting of a series of high peaks, Gayasan has long been sacred for Buddhists, so its name was changed to Gayasan in honor of the Buddha's preaching in India.
It takes 2 days and 1 night to climb the whole of Gayasan, starting from Sudosan, but most travelers visit the park for just 1 day. The most popular route passes through the Hongnyu-dongcheon stream to Haeinsa to the peak, Sangwangbong.
Admission to the park is W1,300 adults, W600 teens, W300 children. The park is open from sunrise to sunset daily.
There are campgrounds in Haeinsa and near Baegun-dong, but these facilities are used less frequently since new roads have been built, making it easier to get in and out of the area. Camping fees range from W3,000 to W6,000, depending on the size of your tent. Parking costs W4,000 to W6,000 per day. There is one midsize hotel and several motels and minbak near Haeinsa. In Baegun-dong, there is one small hotel and a couple of yeogwan. Most people make a day trip to the area and choose not to overnight here.
To get to Gayasan from the Daegu Seobu Bus Terminal, take a bus bound for Haeinsa and get off at the last stop. Buses run every 20 minutes and the ride takes about an hour.
Driving, take the 88 Olympic Expressway (road 12) to the Haeinsa IC. Then take local road 1084 toward Yacheon-li, take national road 59, and follow the signs to Haeinsa and Gayasan.
The official site for the national park is http://english.knps.or.kr/Knp/Gayasan/