The hoopla highlights the past at a time when the township's core, King of Prussia, is vaulting into a glitzy future, with its massive freeway nexus, one of the largest shopping malls in the United States, a convention center and a new casino.
The King of Prussia Business Improvement District has set up 12-foot-high LED markers at key entry points to give visitors "a sense of place." But most people who see the signs are just that - visitors.
Upper Merion has 27,000 residents but 58,000 workers. The mall and convention center bring in about 10 million visitors a year, by township estimates.
For residents, all that imported commerce keeps property taxes low. But it also brings a lot of traffic - especially around Christmas, when, Carson said, "you have to make an appointment to get out on the 202."
King of Prussia's booming profile can also give a false impression of the township, said Supervisor Carole Kenney.
"It's wonderful for our tax base," but it's not representative of the township, Kenney said. "Once you get off the main streets, we are neighborhoods. You don't get that impression if all you do is drive through town."
The neighborhoods of Gypsy Hills and Croton Woods remain almost entirely residential and mostly unchanged over the last century.
Swedeland and Gulph Mills have retained their mixed residential and industrial character - but instead of limestone quarries and steel mills, they have pharmaceutical giant GlaxoSmithKline, The Inquirer and Philadelphia Daily News' printing plant, and the chemical company Lonza.
Swedeland and Swedesburg were among the area's earliest settlements, thanks to Swedes Ford Crossing on the Schuylkill and the rich, limestone-nourished soil. But King of Prussia has always been the heart of the township, and for some, the two have become synonymous.
"The boundaries of King of Prussia have become the boundaries of the township," said Michael Morrison, a local historian who has written books on King of Prussia and cowrote a book being released for the tricentennial. "It's just the way the township evolved. . . . Everything started from the King of Prussia Inn and built out from there."
Founded in 1769, the inn became a popular way-station for soldiers, spies, and other travelers. It was a day's horse ride from Philadelphia and near Valley Forge, with all the amenities of a modern-day turnpike service station. "You had a barn where the horses could be fed, you had a wheelwright . . . a blacksmith" and a place to stay for the night, Morrison said.
Although the inn was a popular destination for 200 years, everything around it remained agricultural - and not highly regarded by people in the region.
"Wayne was the Main Line. King of Prussia was the hicks; they were the farmers," said Marianne Hooper, township librarian and longtime resident.
Emma Carson recalled a similar dismissiveness from her future mother-in-law, a housekeeper in Bryn Mawr in the 1940s. "People would say, 'Where's Dave's girlfriend from?' She'd say, 'Oh, up country someplace.' "
That changed virtually overnight when the Pennsylvania Turnpike, the Schuylkill Expressway, and the King of Prussia Plaza were built, with the inn in the middle. The inn was closed, and then moved, and the rest is history.
Contact Jessica Parks at 610-313-8117, @JS_Parks or firstname.lastname@example.org.
For a list of tricentennial events, visit uppermerion300.org.