Mercer County Engineer's Office


In 1800, when Mercer County was formed from Allegheny County, there were 3,228 residents. Four years later, it was divided into six large townships. By 1840, the population had grown to 32,873. The initial road system in the county followed old Indian trails. Stream crossings were either made by fording the shallow portions of the streams, or small log or stone bridges were constructed. These often washed out after every major storm.

 As additional townships were formed and the road system expanded, it became necessary to construct more substantial bridges. With so few people living in the rural areas of the county, it was often too expensive for the townships to build a bridge. Whenever a bridge was necessary and the cost was more than the townships could afford, they petitioned the courts for appointment of Board of Viewers.

 The court would appoint three individuals to view the site and report their findings to the court. The viewers would examine the location of the proposed bridge and ascertain that it would be a worthwhile and necessary public improvement. The viewers would also, on occasion, recommend the size of the structure and estimate it's cost.

 The court would consider the petition and the Viewers report, and would generally approve construction of the bridge if a bridge was indeed necessary. The court order for construction would determine if a bridge was to be owned by the county or township upon completion, and would also determine which entity would pay for the structure.

 As a result of these court orders, Mercer County became owner or partial owner of 248 bridges. There are also 420 state owned bridges. Most of these may have started out as county or township bridges prior to many of the roads being taken over by the state. There are also an unknown number of township or municipal bridges and culverts in the county.

 The oldest bridge the county owns, the Kidd's Mill covered bridge. It was built in 1868 by the Smith Bridge Company.

 The next oldest bridges the county currently owns are 20 bridges that were built between 1880 and 1909. These bridges were typically built by bridge companies that proliferated in this era. Local masons would erect cut sandstone abutments and a bridge company would provide and erect the bridge superstructures. The Penn Bridge company from Beaver Falls and the Canton Bridge company from Canton, Ohio provided most of the bridge superstructures. Their bridges could be ordered from a bridge catalog, much like the Sears mail order catalog. A typical small bridge would cost about $300 for the abutments and $200 for the superstructure, complete in place. Most of the stone abutment foundations were founded on a log mat.

 The bridges built from the 1910's to the end of the 1930's were designed by County Engineers and were built by local contractors, although some were still built by bridge companies. Lewis Burnside, Frank Graham, and John Harris are listed as the engineers for the structures built during this period.

 During the decade of the 1940's, only three structures were built, and all were located in the city of Sharon. These were designed by Joe Harris, who was Sharon's city engineer at the time. The downturn in bridge building is probably attributed to diverting resources to the war effort.

 From the early 1950's through the early 1970's, George Emery was County Engineer. Most of the steel I-beam bridges with open grid decks in the county were built during this time. The open grid decks were the decks of choice, since they were relatively new and lightweight.

 The county hired consultants Kurtanich Engineers for a short period in the mid 1970's to design county bridges. Several box culverts and concrete bridges were designed by them.

 Mark A. Miller, P.E. was County Engineer from 1978 until his retirement in March of 2017. A wide variety of bridge types from steel multi-girders to prestress concrete bridges to culverts and concrete slabs have been built from 1978 to date. A total of 135 bridges were repaired or replaced, and another nine had plans complete and scheduled at the time of Mr. Miller's retirement.