Today's City of Allentown  is the result of three broad periods of historical development each contributing different types of resources to the City's composition. The first period extends from the City's founding in 1762 through its post Civil War expansion. During this time Allentown grew essentially as a large, country town, primarily serving the surrounding agricultural region with developing industries and strongly influenced by its Pennsylvania German roots. The City's initial physical layout of gridded streets, canal, early railroads, small brick Pennsylvania row houses, and riverside industries characterize this broad period, aspects of which can still be appreciated.
Allentown's second broad period of development extended from about the 1870s into the post-World War II era and saw the City's dramatic expansion as a manufacturing and industrial center. Allentown's urban character matured during this period with the explosion of railroads, large manufacturing complexes, dramatic growth of surrounding working class neighborhoods of developer-built housing, and redevelopment of the City's downtown core as a regional commercial center. Much of the City's present character emanates from this period due to the sheer extent of growth and expansion and the survival of so many buildings and neighborhoods. Much of this development was laid out and fixed in place by the early 1930s. Residentially, it was characterized by block-long banks of sturdy and appealing middle class brick row houses featuring raised front porches, upper floor window bays, and architectural flourishes at the cornice level.
The third broad period of the City's development extends from the decline of manufacturing in the late 20th century through the present, with the transformation of Center City Allentown; infill of housing in the outer neighborhoods; new highways; and suburban commercial, manufacturing, and residential expansion around the edges of the City's pre-1930s boundaries.
Throughout its history, Allentown  has reflected the larger trends of the U.S. economy. A town carved out of the original Penn purchase, Allentown transitioned from a small farming village into an industrial hub for silk, automotive products, breweries, and later, the first transistor radio and modern electronics. In the 1970s, its industrial dominance began to fade as factories consolidated. Today, the community reflects the country's change to a knowledge economy. Healthcare and office jobs are emerging as key sectors in the economy and many workers are employed by the logistics industry, which is bolstered by internet commerce.
Shifts in the economy have caused changes in Allentown's population as well. With the rise of industrialization in the 19th century, large numbers of German and Irish immigrants arrived to the area. The shrinking of major industries in the 1970s caused the city's population to decline. However, since 2000, a new wave of immigrants has moved into the city, which has contributed to Allentown becoming the third most populous city in Pennsylvania.
In 1762, Allentown was originally named Northamptontown by its founder Chief Justice of Pennsylvania William Allen. Despite its formal name, from its founding, nearly everyone called it "Allen's town." Northamptontown played an important role in the American Revolution in 1777 when the Liberty Bell was brought to the area to be hidden in what today is the Zion's Reformed United Church of Christ in downtown Allentown.
In 1838, the opening of the Lehigh Canal provided Allentown with a connection for the passage of goods. The canal immediately opened markets for goods produced in the area, including iron, lumber, and lime, and served as a major transportation thoroughfare.
In 1838, the city officially adopted the name Allentown. Allentown's industry boomed in the mid-19th century. The iron industry took off, supported by arrival of the railroad in 1851 when the Lehigh Valley Railroad Company opened its station.
In 1881, Allentown's silk industry started with the Adelaide Silk Mill, and greatly expanded in the early 20th century. The abundant labor, steady water and energy, and close proximity to the large markets of Philadelphia and New York City, caused the region to become the second largest producer of silk in the world.
In 1895, the first trolley line arrived along Hamilton Street and growth continued in the late 19th century. The trolley opened new areas for development to the west, allowing residents to take the trolley to work. One of the city's neighborhoods spurred by the trolley line was the West Park neighborhood.
In 1898, the Soldiers' and Sailors Monument commemorating the soldiers and sailors of Allentown from the Civil War was installed in Center Square. Development of Hamilton Street continued with Center Square as the heart of the downtown business district.
In 1905, Mack Trucks, one of the most important manufacturers of trucks in the 20th century, opened its initial plant in Allentown along the Little Lehigh Creek North. The company played a major role in the production of trucks during World Wars I and II and sold trucks across the world.
In 1928, the PP&L Building was constructed on Hamilton Street and the vibrancy of Allentown continued through the 1920s. It was not only the highest skyscraper in town but selected by the Encyclopedia Britannica as one of the best examples of Art Deco architecture.
In 1947, Western Electric constructed a factory at 555 Union Boulevard for the production of television tubes and transistors. After World War II, Allentown remained a vibrant economic center. Trolley service was discontinued in 1951, and the City began a major project to renovate the shopping areas along the street. Stores such as the renowned Hess Brothers Department Stores held many special events and hosted celebrities.
In the 1960's and 1970's, growth slowed in Allentown as industry and service businesses declined. The industrial base of Allentown and the Lehigh Valley was undermined as many plants and mills closed including the Neuweiler Brewery in 1968, multiple Mack Truck plants in the mid- 1980s, Bethlehem Steel in 1995, and Hess Brothers Department Stores in 1996. The end of the trolley era created increasingly clogged streets. The construction of shopping centers in suburban areas outside of the city created the eventual shift of shopping off of Hamilton Street. The City worked to halt this economic decline, including the installation of canopies along Hamilton Street from the 1970s to 1999 to mimic the feeling of an indoor shopping center.
Allentown as described in 1940 
Allentown (92,563 pop. [1930 census]), peopled largely by Pennsylvania Germans, lies at the southern base of the Lehigh Mountains in eastern Pennsylvania, with Bethlehem adjoining it on the east. Both lie in the corn, potato, and fruit-growing valley of the Lehigh River, which flows through both cities.
Allentown's business section, dominated by the city's lone skyscraper, a 22-story building at 9th and Hamilton Streets, radiates from the central square along thoroughfares lined with modernized stores and up-to-date shops. Street-light standards are adorned with metal bowls holding flowers in summer and evergreens in winter. The principal industrial sections extend along the Lehigh River and Jordan Creek in the city's eastern part, and along little Lehigh Creek in the south. Close to the mills and factories are the workers' homes: twin or row houses of red brick, with compact lawns and gardens. In the city's northern part are older two-and three-story dwellings of the nineteenth century, now converted into apartment houses. Toward the western extremity are newer residences set amid trees, lawns, and shrubbery.
About 23 per cent of Allentown's population is foreign born-chiefly Austrians, Germans, Czechs, Slovaks, Poles, Hungarians, and Italians; there are less than 500 Negroes. The Pennsylvania Germans, who constitute two thirds of the population, cling as tenaciously to their old traditions as to their curious but expressive idiom. Folk festivals, singing bees, and plays in the Pennsylvania 'Dutch' dialect help to preserve the tradition. Hundreds of Pennsylvania Germans each February attend a dinner in the Masonic Temple to pay tribute, with traditional rites and ceremonies, to the groundhog as the supreme weather prognosticator. All participating must speak the dialect throughout the evening. Numerous family reunions are held annually in near-by parks during the summer, while folk dances, songs, and drills are presented by school children at the fair-grounds.
Allentown is among the few large Pennsylvania cities where newspapers still carry columns written in the dialect. Although English predominates on the streets, there is a tendency to enunciate the 'v' with open lips, to soften the hard 'g' into 'ch,' and to use too frequently such words as 'already,' 'yet,' and 'once.' Here also are heard such colloquialisms as 'the pie is all' (all gone) and 'it wonders (mystifies) me.'
Immigrants from Baden, Wurttemberg, Rhenish Bavaria, Alsace, Darmstadt, and other parts of Germany came to eastern Pennsylvania as early as I723, some settling near what is now Allentown. In I735 William Allen, later chief justice of the State supreme court, acquired a large tract of land in this section from Joseph Turner, who, according to early records, had obtained it from Thomas Penn in 1732. In the I750's Allen erected a hunting and fishing lodge here, but not until 1762 was a town laid out.
Known as Northampton or Northamptontown, it was then bounded by the present 4th, 10th, Union, and Liberty Streets. Its early growth was slow; only a few merchants and artisans resided here six years after its founding. During the Revolution, however, arms and other war materials were manufactured in Northampton. A local church harbored the Liberty Bell when it was removed from Philadelphia's Independence Hall in 1777 to save it from falling into British hands.
Until 1803, when a post office was established, residents of Northampton received their mail at Bethlehem. In 1811 the community was incorporated as a borough; the town's economic development was stimulated by erection of a bridge across the Lehigh River in 1812 and by the building of the Lehigh canal in 1829. Nine years later the borough's name was changed to Allentown in honor of William Allen. In 1841 the Lehigh River bridge was swept away by a flood, and in the same year the major portion of the town was leveled by fire. Reconstruction followed, and the town developed far beyond its former size. The eastern boundary of the town was extended to the Lehigh River in 1852, and in 1867 Allentown was incorporated as a city.
The iron industry, established locally in 1847, developed with the construction of rolling mills here in 1860 and a barbed wire plant in 1886. Cement became of economic importance in 1850 with the erection of a mill in Siegfried, a few miles to the north. Today there are 19 large cement plants in the Allentown vicinity. A board of trade, formed in 1881, encouraged diversified new enterprises. The most important was silk; and the first silk mill was opened in 1882. A boom in this industry made the city for a time the largest silk-producing center in the country; today (1940), with more than 3,500 persons employed in 28 mills, it ranks second to Paterson, New Jersey. The cotton textile industry, a close second to silk, dates from the 1890's, when plants manufacturing women's and children's knit underwear were established here. Allentown is known also for its two institutions of higher learning: Muhlenberg College and Cedar Crest College.
Nearby Towns: Catasauqua Boro • Coopersburg Boro • Coplay Boro • Fountain Hill Boro • Hanover Twp • Lower Macungie Twp • Lower Milford Twp • Macungie Boro • North Catasauqua Boro • Northampton Boro • Salisbury Township • South Whitehall Twp • Upper Milford Twp • Whitehall Twp •