The Lehigh Gap Chain Bridge was the longest operating iron chain suspension bridge ever constructed. This engineering feat eclipsed its neighboring mega-marvel, the Lehigh Navigation, by both having been constructed earlier and having been in operation even after the canal ceased operations. 

The Lehigh Gap Chain Bridge was constructed in 1826, three years before the Lehigh Navigation began operations. It operated until 1933, two years after the Lehigh Navigation ceased operations. This amazing bridge lasted for 107 years. Quite a feat considering modern bridges are routinely replaced every fifty years.

With minimum damage, this bridge braved through several floods that destroyed the Upper Division of the Lehigh Navigation and many of the Lehigh River crossings.

George Ashman of Palmerton remembers Lehigh Gap Chain Bridge—although he was only seven years old when it was demolished in 1933. He remembers sitting with his younger brother in the back seat of his family’s 1920-something blue Essex as it headed toward the Chain Bridge on their weekly trip to Allentown.

What he most remembers was the road descending to the bridge tollhouse. The road and the tollhouse still exist. The road drops toward the tollhouse and makes a ninety-degree turn to the right—where, without sufficient warning, it crosses the Jersey Central, now Norfolk Southern, tracks at grade. Ashman remembers being frightened at that curve and wonders how many wrecks took place there.

The Lehigh Gap Chain Bridge was constructed in 1826 as a replacement for an 1818 wooden bridge that was washed away in an 1825 flood. The wooden bridge was built by General Thomas Craig II, a veteran of the Pennamite and Revolutionary Wars and an early settler of the Lehigh Gap. 

Craig recognized that the Lehigh Gap was the only practical passage to the frontier that was opening along the northern Lehigh River. The road from Easton to the Susquehanna passed through the Lehigh Gap. It was the only connection between the Moravians in Gnatten Heutten with their church’s home in Bethlehem.

At the Lehigh Gap, Thomas Craig built a hotel, the Craig Inn. The Lehigh Gap soon had the second post office, after Lausanne, in what would become Carbon County. Travelers through the Lehigh Gap were required to cross the Lehigh River.

During the low water in the summer, a crossing was possible a mile south of the Lehigh Gap at Kuntz’s Ford. During high water or in the winter, crossing at Kuntz’s Ford was extremely dangerous. It was sometimes possible to cross the Lehigh at a Gap location called Weider’s Crossing. Here, Craig built his first bridge.

After the wooden bridge was destroyed, Craig organized a private company to build a bridge that could survive the Lehigh floods. The Lehigh Water Gap Bridge Company was formed in 1826 to build the bridge. The bridge cost $1,200 to construct and was financed by the sale to 35 investors of 316 shares at $25 each. The investors would be repaid by the collection of tolls for crossing the bridge.

The Bridge Company selected Jacob Blumer, a bridge engineer in the Lehigh Valley. Blumer chose to build a suspension bridge supported by chains, a technique patented by James Finley in 1808.

Finley constructed his first chain bridge, a 70-foot span, connecting Uniontown to Greensburg, Pennsylvania across Jacob's Creek Bridge, in 1801. This design demonstrated the integration of a suspension design, the use of wrought iron chains, and a stiffened deck in a successful bridge design. During his career, Finley would have forty chain bridges constructed.

In 1811, a Finley Chain Bridge was constructed across the Lehigh River at Northampton. The structure consisted of two whole and two half span lengths for a total length of 475-feet. It was the first multi-span suspension bridge ever built.

The chain suspension bridge design would be replaced by the iron, and later by the steel cable suspension bridge. Ironically, the first iron suspension bridge was built by the designers of the Lehigh Navigation, Josiah White and Erskine Hazard. Before coming to the Lehigh coal fields, they operated a nail and wire factory near Fairmont Park along the Schuylkill River in Philadelphia. When the Schuylkill Chain Bridge collapsed in 1811 under the weight of a herd of cattle, they configured a temporary wire rope “Spider Bridge” to cross the Schuylkill River.

Later, Hazard would invent a machine to continuously spin iron wire into cable. His son, Fischer, took over the business and built a factory in Mauch Chunk, current Jim Thorpe, that is the home of the Carbon County Cultural Project. John Roebling adopted the continuously spun iron wire cable in his design of the Brooklyn Bridge—opening the door for wide-spread adoption of cable suspension bridges for crossings of large bodies of water.

After the Chain Bridge was completed, the Lehigh Canal was constructed to pass underneath. The bridge survived the 1841 flood that damaged the Upper Division of the Lehigh Navigation, with only damage to one link and the west abutment, although the cost of repair, $3,882, was more than that of the original bridge. It withstood the 1861 floods, which destroyed the Upper Division, without damage. It also survived the floods of 1901 and 1902.

The Lehigh Gap Chain Bridge spanned a length of 160-feet, 30-feet above the normal level of the Lehigh River. It had a 16-foot wide deck. Islands were constructed in the Lehigh River and two piers of local stone and locally quarried cement, were constructed to support the chains.

The wrought iron chain was constructed of eight-foot long, 140-pound links. The links were made at the Lehigh Furness in Washington Township, Dinkey Furnace in Ashfield, Maria Furnace at Harrity and the Clarissa Furnace at Little Gap. Iron ore was transported from Ironton, Orefield and New Jersey. Oak for the decking came from local forests. Over the years, the Craig family maintained a presence in the Lehigh Gap and was involved in the operation of the Chain Bridge.

Tolls initially were one cent for a sheep, swine or pedestrians. Those walking to church were free. Two cents were charged for a horse or cow. A horse and rider were charges 6-1/2 cents. A loaded wagon pulled by four horses cost 25 cents, and a coach was 31-1/2 cents. Towards the end of its service.

In 1900, the free trips for churchgoers ended. By 1916, the Chain Bridge was carrying automobiles, even military convoys during World War I—an application unforeseen by the bridge’s engineer. The bridge performed flawlessly and the tolls increased. Wagons were charged at a rate of five cents per horse.

Bicycles, motorcycles and wheelbarrows passed at two cents. Riders and cattle were five cents. Automobiles paid ten cents and, for truck, the rate was proportional to the weight—with moving vans charged 50 cents for the passage. One hundred trip tickets were available for buses.

In 1925, a fire of suspicious origin burned the wooden members of the Chain Bridge. It was repaired but it was also recognized that the Chain Bridge was operating way beyond its design life. It was replaced in 1933 by the current Rt. 873 - Appalachian Trail Bridge. When the Lehigh Gap Chain Bridge came down in 1933, it was the oldest Finley chain bridge in operation.

Parts from the Lehigh Gap Chain Bridge, as well as spare chains that had never been used, were grabbed by collectors. In 1936, the Palmerton Board of Trade placed six of the chain links in a memorial to the Chain Bridge in its town park. A zinc plaque is mounted on a stone monument. It features an etching of the Lehigh Gap Chain Bridge by Irving Jelley Sr. The wrought iron links, now close to two centuries old, were never painted and do not show signs of rusting.

Later, the meandering roads on the east side of the Lehigh Gap would be straightened. The new road bypassed the Craig Inn and put it out of business. In 1963, construction of Rt. 248 destroyed the last vestiges of the Lehigh Gap community.