| Baguashan Tunnel | |
| Location: | Taiwan |
| Coordinates: | 24.0467°N 120.6044°W |
| Status: | Open |
| Route: | Provincial Highway 76 |
| Startwork: | 15 November 1996 |
| Opened: | 29 April 2005 |
| Operator: | Directorate General of Highways |
| Length: | 49283NaN3 (westbound) 49353NaN3 (eastbound) |
| Lanes: | 4 |
| Speed: | 80km/h |
The Baguashan Tunnel, on Provincial Highway No. 76, Taiwan, transverses Baguashan (八卦山) between Lincuo IC. (林厝交流道) and Zhongxing JCT. (中興系統交流道). The length of the north tube for westbound traffic is 49283NaN3. The length of the south tube for eastbound traffic is 49353NaN3. Connecting Yuanlin, Changhua and Caotun, Nantou, its opening significantly reduced the travel time between Changhua and Nantou.
It was the longest highway tunnel in Taiwan when opened to traffic in April 2005, until the top rank moved to Hsuehshan Tunnel in National Highway No. 5 in June 2006. It is now the second longest highway tunnel in Taiwan.
The first step allowed small vehicles on 29 April 2005.
The second step allowed buses on 1 January 2006.
The third step allowed heavy trucks on 1 January 2007. But vehicles with hazardous materials or being too long, too wide, too high, or too heavy (more than 21 tons in gross weights, including combination vehicles like full-trailers and semi-trailers) are still remain banned.