Everything closes, not some of it
Odaesan National Park closes trails twice a year, and it keeps some sections open through both periods. Gyebangsan is not among them. All 7.5 km of trail here shuts: 6.5 km from Unduryeong to the Nodong valley, and the 1.0 km from the summit to the junction. The open sections in those periods are all on the Woljeongsa and Sogeumgang side of the park, an hour away.
The autumn 2025 closure ran 15 November to 15 December, and the park office confirms walking resumes on 16 December. The spring 2026 closure began on 3 March. In spring 2025 the equivalent period ran 4 March to 15 May.
The park’s own document gives two end dates for the 2026 spring closure: one place says 5 May, another says 15 May, in the same file. Ten days is enough to ruin a trip, so check the current notice before you go.
And there is a third calendar in play that is easy to confuse with the first two. The national fire-risk season for spring 2026 opened on 20 January, roughly six weeks before any path on this mountain closed. A fire-risk season is not a closure. The park also says the closures are not only about fire: it cites the resting season for wildlife and plants as a reason in its own right.
Two courses that are really one climb
Both official courses start at Unduryeong, a pass on Route 31, and both are 8.9 km. They share the first 4.1 km to the summit, three hours of it, and then part company.
The first drops 4.8 km in three hours past the yew grove and down the Nodong valley to the entrance of Yi Seung-bok’s birthplace: 6 hours in total. The second takes a gentler ridge 4.8 km down to the Gyebangsan car park in 2 hours 10 minutes, for 5 hours 10 minutes overall.
The figures here are unusually solid. The course data, the course text and the printed trail map all give the same numbers, and the segments sum exactly in both distance and time. The single crack is the second descent: the course page says 2 hours 10 minutes, the map says 2 hours. We follow the course page, since the distance comes from the same record.
Neither course is labelled one-way or round-trip. Both finish at a different place from the start, so plan the return before you set off.
Gentle is not the word the park uses twice
The park describes Gyebangsan as evenly balanced between gentle and steep, and describes the wider district as soft earth mountains with flat summits and easy connecting ridges. Both are true of the map. Neither is what the course text says about the climb.
That text says there are three ascents below the summit that leave you gasping. Below the yew grove on the way down it warns of rock slabs breaking through the path that you can slip on, and then a boulder field where the stones move under your feet — it names ankle injuries specifically.
We rate both courses at our hardest grade. The park rates them in the middle of its own three, and we have gone a step above that deliberately: 8.9 km at under 1.5 km an hour is a slow pace by any measure, and the terrain text supports the harder reading rather than contradicting it.
The gates close early here
Timed access applies at three points on this mountain: the Unduryeong pass, the junction, and Ongdalsaem. Entry runs 05:00 to 14:00 from November to March, and 04:00 to 15:00 from April to October.
Those are an hour earlier at both ends than the equivalent gates in most national parks, and the arithmetic matters: against a six-hour course, arriving at the 14:00 cut-off is not a start, it is a mistake. In the winter window, when the mountain is worth coming for, you want to be on the pass at first light.
What the park asks you to carry
For winter the park is direct: you must be equipped with crampons, gaiters and other cold-weather gear, and you must stay on the marked trail. Its snow-preparedness notice adds two more — go in a party of at least two, and do not walk when a weather warning is in force.
It is worth being clear about the status of that. No regulation sets a specification and nothing indicates checks at a gate. It is the park stating what it expects on its own snow, not a barrier you will be stopped at. On a 1,577 m summit in February that distinction is academic.
The same material warns that high wind brings down trees and throws debris, and tells you to move away from dead timber and steep ground and find shelter rather than push on.
Nothing to pay, nothing to book
The park’s reservation system lists no controlled sections anywhere in Odaesan, so nothing here needs booking. There is no entrance fee item in the charge schedule for this park.
Parking is a gap rather than a charge. The park service states that it runs no car park at Gyebangsan and that there is no state land there for it to collect on. Whether anyone else charges at Unduryeong or at the lower car park is not published — neither county gives a rate.
One thing you may have read elsewhere and can stop worrying about: Woljeongsa ended its cultural property admission charge on 4 May 2023. It is also on the opposite side of the park from these trailheads.
The yews, and what the numbers cannot tell you
At 1,577 m Gyebangsan is the highest point in Odaesan National Park — higher than Birobong — and the park describes it as the fifth highest mountain in Korea. The printed trail map gives 1,577.4 m.
Near the summit there is a large grove of yews, some of them over a thousand years old, which the park lists as the reason to come after the snow itself. A dogtooth violet colony flowers lower down in spring, and the park offers those two as the bookends of its seasons.
There is one number nobody publishes, and it is the one that would tell you most: the altitude of Unduryeong. The pass is high, so the climb is far less than 1,577 m — but no official source gives a figure and the park lists no cumulative gain for either course, so height gained is not stated. Judge the day by 8.9 km and six hours instead.
How to plan it
Decide the date first. That is unusual advice for a mountain, and it is the right order here. Between 16 December and early March you can walk it, and that is what you came for. Outside that, the mountain is open from the end of the spring closure through to 14 November, and it is a fine walk in autumn — but it is not the mountain in the photographs.
Then pick a course by how you are getting back. Both are 8.9 km from the same pass and both end somewhere else. If you can only arrange one pick-up, the car park finish is fifty minutes shorter and the descent is kinder.
Then go early. The gate shuts at 14:00 in winter and the walk is six hours, which settles the question of when to set off.