The vicinity of the town of Pleasantville was settled as early as the 1830s. Because of the number of families in the area having the surname Dubbs, the village was, at first, called Dubbstown. In the year 1833, William Hancock constructed the first grist mill in the area. In the same year a mercantile was established by Moses Dubbs. Seven years later, in 1840, a tannery was started by Samuel Dubbs.
The town was laid out between 1845 and 1860. It was incorporated into a borough on 10 March 1871. Benjamin Bowen Jr., owned most of the land that was laid out in lots. Bowen sold the land to several others in large tracts, and they then subdivided them and sold them to individual lot purchasers.
In 1855, the post office that had previously (in 1812) been opened at the village of Spring Meadow under the name of Alum Bank, was closed. The region's postal services were moved two and one-half miles west. It was housed in a building along the east side of Main Street, midway between Alleghany and Locust Streets. The name: Pleasantville, though, was already in use by another post office in Pennsylvania, so it could not be used here. Instead, the name Alum Bank was given to the new office at the town of Pleasantville. And up to the present day, the borough is officially named Pleasantville while the addresses are all named with Alum Bank numbers. It should also be noted that the post office, between 01 December 1895 and 01 December 1905 was spelled 'Alumbank.'