An extension to the town of Dorchester in southwest England, the community was designed according to his architectural principles and demonstrates how different his approach to public life has been from that of his mother, Queen Elizabeth, who died on September 8, aged 96.
The late queen gave little away about her opinions and preferences and was careful to avoid controversy.
As Prince of Wales and Duke of Cornwall, Charles shared his views on subjects that interest him such as architecture, environmental protection and alternative medicine.
He signalled in his first address as king last week that he would be more reserved from now on, but Poundbury stands as a physical, populated testimonial to his lifelong passions.
The land on which Poundbury is built is part of the Duchy of Cornwall.
As Duke of Cornwall before ascending to the throne, Charles owned the land, so when it was designated for the expansion of Dorchester, Charles saw an opportunity to put his ideas about architecture into practice, commissioning architects and developers to realise his vision.
"I was told it was completely uneconomic. So everybody was against it, from the Treasury to everybody else," Charles told an ITV documentary in 2019.
"In the end, I was determined to stick to my guns. I got on regardless of the endless criticism and carping and shouting and screaming. Because I've always believed in the long term."
Critics say that with its lack of road signs and oddly curved streets, Poundbury is more like a toy town than a real place, betraying an amateurish approach.
But others admire Charles for sticking to his convictions and facing down naysayers for over 30 years, to create a community that is popular with its roughly 4,500 residents and attractive to newcomers.
Construction of Poundbury began in 1993 after Prince Charles had set out his ideas in the 1989 picture book "A Vision of Britain: A Personal View of Architecture".
He expressed his preference for "buildings that have grown out of our architectural tradition and that are in harmony with nature," deriding post-war architecture and modern urban planning for its "sheer unadulterated ugliness and mediocrity."
A single road sign, indicating that roundabout rules apply to the area around a statue of Charles's maternal grandmother, Queen Elizabeth the Queen Mother, is the one concession made to traffic signage.
Along with the wonky roads, the absence of signs is supposed to force drivers to slow down and give way to pedestrians.
The unusual approach to traffic management, along with the variety of building styles that draw on different aspects of Britain's architectural heritage, contribute to Poundbury's distinctive look.
Businesses are integrated into the design, with about 2,500 jobs in shops, cafes, offices and factories.
A local chocolate maker is among the development's success stories.
For a time, a cereal manufacturer clogged up the genteel streets with lorries, but it has since moved.
Despite initial scepticism, locals are warming to Poundbury, said 64-year-old Chris Moyle, from nearby Weymouth, whose mother is considering moving to the development.
Rising house prices show Poundbury's appeal, though critics say it is unaffordable for many people.
The average property price in Poundbury over the last year was over 400,000 pounds ($463,000), according to property website Rightmove.
The Duchy of Cornwall office which manages the development says it meets official targets for social housing.
Local councillor Richard Biggs said the Poundbury has a "Marmite effect" on most people, referring to a famously divisive yeast spread that people tend to either love or hate.
Biggs told Reuters that while some things have "worked brilliantly" others have been less effective as the vision of the king and the architect's clashes with planning rules and restrictions.
With Charles becoming king, his son William now succeeded him as Duke of Cornwall and comes into possession of the land.
William has not shown the same interest in architecture previously, and planners expect no interference from him as the building continues.
Poundbury's former estate director, Simon Conibear, said that despite small modifications to the original plan, the development was on course to being completed while upholding the king's original principles.