The Monongahela Bridge, opened in 1818, was the first bridge to span the Monongahela River in Pittsburgh. It was also the first bridge of any kind built in the city to accomodate everyday pedestrian, livestock and wagon traffic. The bridge replaced a ferry service that had operated between Smithfield Street and the southern shore for several years.

In 1810, a law was enacted in the State Legislature calling for the construction of two bridges in Pittsburgh, across both the Monongahela and Allegheny Rivers. The initiative was put aside due to the War of 1812, then re-enacted in 1816. Construction of the two abutments and seven Monongahela Bridge piers, which would support the span across the river from a point along Smithfield Street, began shortly afterwards.

Diagram showing the Monongahela Bridge.

Designed by famous early-American engineer Lewis Wernwag and constructed by John Thompson, work on the bridge began in June 1818, and by November the final arch was put in place. Built at a cost of $102,000, the elegant 1500 foot covered wood bridge, made of wood and iron, opened to much fanfare. Owned by the Monongahela Bridge Company, it was the only bridge to span the Monongahela River, linking Pittsburgh to the growing municipalities to the south.

Not long after, Wernwag's Allegheny Bridge, another covered bridge located at Sixth Street, was completed, linking Pittsburgh with Allegheny City to the north. Historians then proclaimed that Pittsburgh had achieved what no other American city or town had ever yet done, constructing two splendid bridges over two mighty streams, within just four hundred yards of each other.

1828 Map of Pittsburgh showing the Allegheny and Monongahela Bridges. The other bridge shown
across the Allegheny River was part of the Pennsylvania Canal.

An etching of Pittsburgh, drawn in 1843, showing the three covered bridges then standing: the Monongahela, Sixth
Street and Penn Canal Bridges. Much of the city shown here was destroyed in the Great Fire of 1845.

Crossing the Monongahela Bridge required payment of a toll. The toll collector was housed in a small apartment built above the barn-like portal of the Pittsburgh side. The list of tolls was as follows: Foot passengers, 2 cents; vehicles of four wheels and six horses, 62 1/2 cents; vehicles of two horses, 25 cents; vehicles of one horse, 20 cents; horse and rider, 6 cents; horse alone, 6 cents; individual heads of cattle, 3 cents; individual heads of sheep, 3 cents.

The Monongahela Bridge was a huge success, and quite profitable to it's stockholders, which included the State of Pennsylvania. The bridge was damaged and put out of service for a short time in 1832. It was struck by a runaway riverboat which caused the collapse of two sections.

  
The Monongahela Bridge in 1832 (left) after being damaged by a runaway boat, and
thirteen years later (right) as it burned during the Great Fire of 1845.

The Monongahela Bridge after the Great Fire. Nothing remained of the structure but the stone piers.

Aside from that mishap, all went well for the Monongahela Bridge Company until April 10, 1845. This was the day of the Great Fire of 1845, which reduced the wooden span to a smoldering ruin in a little under fifteen minutes.

One year after the fire a suspension bridge was built in its place by the famed designer John Roebling, using the existing stone piers from the damaged bridge. The replacement span was also called the Monongahela Bridge. The bridge retained that name until 1861, when the South Tenth Street Bridge became the second span to cross the Monongahela River. At that time, the Monongahela Bridge gradually took on a new title, Smithfield Street Bridge.