Somerfield borough was laid out by Philip D. Smyth, in 1818, as the town of Smythfield. It was situated where the National road crossed the Youghiogheny river and was laid out on land warranted to Jacob Spears, April 17, 1769, fourteen days after the land office at Philadelphia was opened for the sale of lands west of the Allegheny mountains. There is a strong probability that Jacob Spears was the same Spears by whom Capt. Steele sent the proclamations to the trespassing Turkeyfoot settlers in 1768, and that he, himself, was one of the trespassers. Spears sold the land to Smyth in 1816. Smyth already kept a tavern somewhere in Addison township, and this probably was the place, although he also owned the Richard Hoagland lands, which were further away from the river.
The famous stone bridge was completed July 4, 1818, when it was turned over to the government. The occasion was made a gala day such as had never seen before in these mountains. President Monroe, with several members of his cabinet and other officials, were present, and all the countryside turned out in honor of the occasion. The Endsley stone house, built in 1818 by Kinkaid, Beck and Evans, the bridge builders, was always a noted tavern. Its walls and foundations are as firm today as when first laid. Its first landlord was James Kinkaid, who was followed by John Campbell, Capt. Thomas Endsley, and others. Capt. Endsley taking it for the third time in 1847, since which time it has remained in the Endsley family.
There was a log tavern built by John Campbell about 1823, and first occupied by him. In 1823, Kinkaid, the bridge builder, built a brick tavern on the south side of the street that also became famous. It was the relay house of the Good Intent Stage Company, the Endsley House being the same for the older Stockton lines. In the early days of the pike, Somerfield was essentially a stage town. At its taverns were kept the relay stations for the teams of the different stage companies, and their patronage was more largely from the traveling public than from what was known as the road traffic. Most of the drivers of the many stages also lived here, and the town, along with its neighbor, Petersburg, was the scene of more bustle and activity than any other town in the county.
It is not known when the name of the town was changed from Smythfield to Somerfield, but it must have been before 1830. Dr. William Fry was then postmaster of Somerfield, and was probably the first physician who located there, living there to the end of his life. He is still remembered not only as an able medical advisor, but as a gentleman in all the rations of life.
With the decay of the pike, the town declined until it contained only dilapidated houses and about eighty inhabitants. In 1883 Somerfield had two stores, one blacksmith-shop, a spoke-factory operated by William Endsley & Son, one wagonshop, one cabinetshop, one boarding-house, one physician, Dr. T. Jacobs, and one church, Methodist.
With the building of the Confluence and Oakland railroad, which passes through it, the business life of the place once again quickened, and it entered on a new era of prosperity with a largely increased population. In 1906, there were five stores in the town. Somerfield was incorporated as a borough in 1893. John W. Endsley was the first burgess. His successors have been: J. B. Jordon, John Close, H. R. Watson, Robert C. Campbell, John Close.
The last chapter on Somerfield was written in the 1940s when it was destroyed to make way for a new dam. Flooded, it lies under the Yough Lake. Its remains, which consist of foundations, streets and its bridge, have been known to reappear during years of extreme drought.