The delegation, led by former national security adviser Stephen Hadley, also met outgoing president Tsai Ing-wen in a show of support for the government.
The visit comes a day after Lai Ching-te from Taiwan's ruling Democratic Progressive Party (DPP) swept the presidential polls in a crucial election for the self-governed island amid a concerted campaign of pressure by China.
Beijing, which has branded Mr Lai a separatist and “troublemaker”, claims the self-governed island to be its own territory and repeatedly criticised the US for backing its democratic process.
The Chinese foreign ministry criticised the "incorrect actions" of the US and other Western nations, including the UK and Canada, in congratulating the president-elect.
Mr Lai's victory prompted Nauru – a small Pacific island nation – to sever diplomatic ties with Taiwan on Monday and restore bilateral relations with China instead, saying the move was in the country's "best interest".
Mr Hadley said he and other US delegates were in Taiwan to convey congratulations on behalf of the American people over the conduct of the election.
"Taiwan's democracy has set a shining example for the world, a democratic success story based on transparency, the rule of law and respect for human rights and freedoms," Mr Hadley said, in comments released by the Taiwanese presidential office.
"We are honoured to have the opportunity to meet with you today to reaffirm that the American commitment to Taiwan is rock solid, principled and bipartisan and that the United States stands with its friends," he added.
"We look forward to continuity in the relationship between Taiwan and the United States under the new administration, and for common efforts to preserve cross-strait peace and stability."
As of Monday, Taiwan shares official diplomatic ties with just 12 nations, but maintains robust trade relations with Western democracies, including the US.
Mr Lai met the group later at party headquarters and expressed his desire for the US to continue to support Taiwan and deepen cooperation with the island.
He said his administration will "keep defending peace and stability in the Taiwan Strait" as his predecessor has done. Mr Lai is expected to take office on 20 May.
Ex-deputy secretary of state James B Steinberg affirmed bipartisan support for Taiwan "based on our unofficial but warm relationship, our insistence on exclusively peaceful means to address the cross (Taiwan Strait) issues, the importance of dialogue and the avoidance of unilateral efforts to change the status quo".
President Tsai said following the election that Taiwan's "need to continue to progress and move forward remains unchanged". "We hope that Taiwan-US relations continue to advance and serve as a key driving force in regional and global prosperity and development," she said.
Mr Lai followed his predecessor Ms Tsai’s example by not actively campaigning for a Taiwanese declaration of independence, a contentious issue even among Taiwanese. Instead, he said Taiwan’s elections and self-governance showed the island was already “a sovereign country” and that he would “build on this foundation” if elected.
Joe Biden reiterated longstanding US policy on the matter on Saturday, just after Mr Lai’s victory was confirmed, saying: “We do not support independence... [for Taiwan].”
The US switched diplomatic recognition from Taipei to Beijing in 1979 and has long said it does not support a formal declaration of independence by Taiwan.
While Mr Lai won the election, the DPP lost its majority in parliament, potentially making it much harder for him to pass legislation.