Trump has alternately offered harsh criticism and praise for Merkel, accusing her of "ruining" Germany with her "catastrophic mistake" of a refugee policy, while also naming her his "favorite" world leader.
Trump is expected to announce a restart of a review of vehicle fuel efficiency rules sought by the auto industry at an event on Wednesday with the chief executives of USA automakers, sources say.
The United States will release its Labour Market Conditions Index for February tonight, after having announced steady jobs growth last Friday.
The day of events was slated to include talks, a news conference, and a working lunch.
According to aides and analysts, Trump's meeting with Merkel is the most important sit-down with a foreign leader since the Republican businessman took office in January. This hour On Point: When Angela Merkel meets Donald Trump.
The reserved German leader herself underlined that she is travelling to Washington not only as Germany's leader, but also as an envoy of the EU. During last year's campaign, Trump once said Democratic nominee Hillary Clinton wanted to become "America's Angela Merkel, and you know what a disaster this massive immigration has been to Germany and the people of Germany".
Merkel and Trump are expected to discuss a range of critical issues, including the future of North Atlantic Treaty Organisation. "I will of course point out that for us, our country and our membership in the European Union are two sides of the same coin", Merkel said in Brussels ahead of the visit.
White House officials said Trump's initial opinion of Putin is operative.