A spokesman says the Republican presidential candidate's plane has landed in the Massachusetts capital.
Romney concluded a seven-day overseas tour on Tuesday after a speech in Poland. His earlier stops were in Britain and Israel.
The three-nation trip was Romney's first as the presumptive Republican presidential nominee. He struggled through a series of missteps and at times drew sharp criticism from British and Palestinian officials.
Speculation is already turning toward Romney's choice of a running mate. His campaign released a statement Tuesday suggesting that the announcement would come soon.