WASHINGTON — President Trump dined at the ornate Georgetown home of a prominent Washington lawyer on Wednesday night with wealthy donors who are expected to play crucial roles in financing his re-election campaign.

The dinner was the latest in a series of donor events associated with a pair of independent groups — America First Policies and America First Action — that are aiming to raise $100 million this year, mostly in large donations, to support Mr. Trump’s agenda and the election campaigns of allied congressional candidates.

Attendees included donors and operatives who are working to raise money for the America First groups, such as the Dallas financial executive Roy W. Bailey and the Oklahoma oil billionaire Harold Hamm, as well as the president’s eldest son, Donald Trump Jr., according to someone briefed on the list of attendees and published reports.

Mr. Hamm and Mr. Bailey are on the board of America First Policies, a nonprofit group that was created to advocate Mr. Trump’s agenda and that has paid for a series of polls and strategy memos about the political effects of the Trump administration’s efforts. America First Action, on the other hand, is a “super PAC” that is raising money to air advertisements in support of Republican congressional candidates allied with the president.