Boneyard Bridge is a location found in Breath of the Wild.
Breath of the Wild
The Boneyard Bridge is located just southeast of Hyrule Castle. It crosses over the Hyrule Castle Moat right where it meets with the Hylia River. East Hyrule Castle is located just to the north and has a dangerous Guardian Stalker, as well as a Stalnox.
In the water near the bridge, Link can find some Hyrule Bass, Hearty Bass, and Staminoka Bass swimming around. Just east of the bridge there is also a circle of rocks. While standing on the bridge, Link can toss a rock into the circle to get a Korok Seed. Link will need to use Cryonis to create some Ice Blocks so that the rock can reach the circle.
To the east of the bridge, on the other side of the Hylia River, Link will find a Raft that he can use to navigate the water. A treasure chest can be found right here as well, which contains a Soldier's Shield. Just southeast of the bridge there is another treasure chest in the water and this one contains five Fire Arrows.
Nearby Korok Seeds
Throw a rock into the ring of rocks found in the east bank of the river. The Cryonis rune can be used to help the rock make it all the way as it is difficult to throw the rock far enough otherwise.