An arch bridge is based on the ancient concept of spanning an opening with a curved structural member. The arch transmits the load from the bridge deck to the abutments on both sides of the span and thus to the ground below. Early arch bridges were built of stone blocks wedged together to form the arch. Short modern arch bridges may use wood or concrete, while longer arch spans are built of steel. Since the arch requires no central support, it can be used to bridge long open spans. The arch can be either above or below the bridge deck. The arch pushes downward and outward against its abutments, which must be heavy to resist the thrust. Since the abutments transfer both horizontal and vertical forces from the bridge deck, arch bridges can only be used where the ground or foundation is solid and stable. The curved arch structure offers a high resistance to bending forces.

Arch bridges can be constructed with the deck above the arch (a deck arch bridge), or the deck can be hung from a segment of the arch which rises above the deck (a through arch or tied arch bridge). In a deck arch bridge, the space between the bottom of the arch and the deck can be solid (a closed spandrel deck arch) or open with supporting vertical members (an open spandrel deck arch).