According to The Palm Beach Post, the couple bought two addresses in Admirals Cove, a “personal resort” and private enclave in Jupiter that comes with a $195,000 (£142,000) membership fee.
Although the purchases cannot be blocked, the Post reports, Admiral Cove residents circulated an email thread last week in which they denounced Mr Trump Jr’s arrival as “a nightmare”. Others have written to the residents’ association with concerns.
One resident complained about Ms Guilfoyle's work as a television personality on Fox News, which was supportive of the Trump presidency, and wrote in a letter to the resident’s association that she and her partner, Mr Trump Jr, would bring “undesirable notoriety” to the estate.
"I believe their membership would bring undesirable notoriety to the club, harm our reputation and have the potential for creating disharmony," the resident said.
Around thirty were said to have complained to the residents’ association overall, with many worried about safety and security surrounding the pair, who are due to move into an address on Mariner Drive, listed at $11 million (£8 million).
Ms Guilfoyle has also purchased the property next door, listed at $9.5 million (£6.9 million), according to the Post.
They are expected to move in after Donald Trump and other family members departed Washington DC on Wednesday, when Joe Biden was sworn in as president.
They are thought to relocate to Florida alongside the former president, who will spend time at his Mar-a-Lago resort on Palm Beach. Ms Guilfoyle also has relatives in the state.
"About half have concerns about safety," said Peter Moore, a general manager of the Admiral Cove property owners association to the Post. "The others have political concerns with what's happened in the last couple of weeks."
Mr Trump, the former president, has faced similar complaints from residents of Palm Beach, who wrote two letters to local officials last month demanding they block his residence at Mar-a-Lago.
Those complaints were thought to have escalated since his supporters stormed the US Capitol on 6 January, with allegations Mr Trump had November’s election “stolen” from him. They were without basis.