The Syracuse Weighlock Building, which now houses the Erie Canal Museum was built in 1850. It was not the first weighing station in the city. The first one, built in 1824, consisted of a chamber at the same level as the canal. There was no building enclosing the chamber and the weighing process was done by the water displacement method. Although the method was accurate, it was so misunderstood by canal boat captains that they called this type of weighlock, "little more than a guess pond."

A new weighlock was built in 1828, but the wood of which it was constructed deteriorated in only five years. The third weighlock, built in 1834, was the first weighing station to have a building along with it. It was more efficient, but, by then, the busy canal was being enlarged to be 7 feet deep and 70 feet wide and soon boats would clog the waterway. By 1845, toll collecting was at a peak and the weighlock could not handle the larger boats and heavy traffic.

The last weighlock was opened on July 22, 1850. It was designed as a simple two story red brick structure with a tin roof, in the Greek Revival style. The first floor housed the Weighmaster's office and sleeping quarters for the night men because the weighlock operated twenty-four hours a day. On the second floor were offices for engineers and repair superintendents.

The weighing process was simple. Boats entered the weighlock chamber. The gates closed, securing the boat in the chamber. Next, water was drained out through an underground culvert to Onondaga Creek. This left the boat resting on a large wooden cradle which was attached to a huge scale mechanism. Tolls were calculated by subtracting the empty weight of the boat from the full weight. Tolls were paid on the difference. Once this was done, water was added to the chamber and the boat was on its way. When all went well, this whole process took about 15 minutes.

Tolls were assessed at the weighlocks but the fee was paid to Toll Collectors at different sites. There were seventeen toll collection locations in all. In Syracuse it was generally located in Clinton Square. Rather than being sent to Albany, money was banked in communities along the Erie Canal. In this way, greater benefit was brought to more communities.

By 1883, more than $121 million dollars had been collected. The tolls not only covered the cost of constructing the canal, but also paid for repairs, operation and even the construction of the enlarged Erie Canal. Tolls were abolished.

The Syracuse Weighlock stayed in service to weigh cargo for shippers and to provide a dry dock for emergency repairs. The building continued to house canal engineers and maintenance officials.

In 1906, the massive scales were removed and the second floor was extended over the lock chamber to provide a drafting room for the state's new "Good Roads" program.

The Erie Canal remained a vital transportation route throughout the Civil War. But, with the emergence of railroads, the Erie slowly began to decline. Thoughts turned to making a canal that could accommodate large barges. So, the Barge Canal was built between 1905-1918 at an initial cost of $101 million. Unlike the Erie Canal, the Barge Canal System, which is still in operation, makes use of natural waterways and needs no towpath.

The last canal boat passed through downtown Syracuse in 1922. Sewers, waterlines and other public services were laid in the old canal bed and then covered with dirt and blacktop to make the roadways. The section on which the Syracuse Weighlock Building faced became Erie Boulevard.

In the 1930's, new office space was created by enclosing the weighing chamber. The NYS Department of Transportation remained in the building until 1957 when its personnel moved across the street into the State Office Building. The building was abandoned and faced demolition. Citizens, led by the Junior League and, later, by Frank Buchanan Thompson, rallied to preserve the Weighlock Building and to create a history museum.

Since 1962, the Weighlock Building has been the home of the Erie Canal Museum which is dedicated to telling the great American adventure story that marks the construction and operation of the Erie Canal. Of the seven weighlocks that once operated on the Erie Canal, the Syracuse Weighlock is the only one remaining. It is the only building of its kind left in the world, and is listed on the National Register of Historic Buildings.