It is a railroad bridge that crosses the San Luis River between eastern Hennigan's Stead in New Austin, USA to Diez Coronas in Nuevo Paraiso, Mexico. Trains departing from Casa Madrugada go across this bridge en route to the MacFarlane's Ranch train station.
- According to Francis Gallagher in Thieves' Landing, He mention a train or wagon being raided on the bridge, or someone falling from the bridge into the river below.
- Butter Bridge appears to have the same bug as Manteca Falls (except the following situation is reversed) where even when the player is on Mexican territory, music that would normally be heard when in New Austin will play, even though the game still recognizes that the player is in Mexico (e.g. bounties obtained in Mexico will still be present).
Uncover every location on the map in Single Player.
Attain 100% List in the singleplayer game completion list.