Those migrations transformed the political landscape here, making it a less likely place for Trump supporters like Roseanne Conner. Kane County went solidly for Barack Obama in 2008 and 2012, and for Hillary Clinton in the 2016 election; in fact, by 2015, Elgin was majority Hispanic, and the median income had risen substantially, too.

In other words, Lanford hasn't changed much, while Elgin, like many other parts of the U.S., has — politically, socially and demographically.

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But that hasn't at all harmed the popularity of the "Roseanne" revival: The show's new season kicked off with sky-high ratings and was quickly picked up for another season.

"It may be kind of ironic that Elgin now is not the Elgin it used to be, but Lanford is. Lanford is still the town it used to be," Tim Brooks, a former network television executive and TV historian, told NBC News.

"But as long as the characters in the show seem to be good and funny people who you'd want to invite into your own home, the show will succeed," Brooks added. "Likable characters enable viewers to put up with pretty much anything. Even Trump.

"But difficult political conversations can come up in the show, because they come up in real life, and families go on. It's what viewers see in their own lives, and they get that and they like seeing it on television."

Inside the Dutch Inn West, Elizabeth Gospodarek, 48, a lifelong Elginite who works at an oil and gas testing company, said Elgin residents still love the show, even if it doesn't portray their city accurately.

"The honesty of the show is spot-on," Gospodarek said, referring to the program's approach to tough family conversations about politics, in between sips of Budweiser.

The Dutch Inn West in Elgin, Illinois. Daniel Acker / for NBC News

The character's affinity for Trump, both on-air (as Roseanne Conner) and off (as Roseanne Barr), doesn't fit the city in real life either, residents said.

"It is crazy to me that she's a Trump supporter because that is so divisive and he is so divisive," Bill DiFulvio, 57, a self-described "independent who doesn't support Trump," said, pointing to the real-life and fictional Roseannes.

The times they are a-changin'

During the first run of "Roseanne," Elgin was a natural place on which to base Lanford.

A pocket watch made by the Elgin Watch Co., in business from 1864 to 1968, is displayed at the Elgin History Museum. Daniel Acker / for NBC News

After the closing of the Elgin National Watch Company, by far the city's largest employer, in 1968, the city underwent a decades-long economic downturn, the effects of which continued into the late 1980s and early ’90s, when the first iteration of the show aired, said Elizabeth Marston, the director of the Elgin History Museum.

But over the last 15 to 20 years, she said, due to a resurgence in manufacturing jobs and an effort to diversify the local economy — the city's largest nonpublic employers last year included two hospital corporations, the Grand Victoria riverboat casino, Fisher Nuts and J.P. Morgan Chase — and an influx of newcomers, many of them Latino, the city has become younger, far more diverse and Democratic.

"Elgin has changed dramatically since the late '80s and 90s," Marston said. "And when you see a shift like that, it then brings in more people who are, themselves, comfortable with that diversity, those values."