The billboard company said the display in the 600 block of South Federal Avenue of Mason City and ordered and funded by the organization, went up last week, The Mason City (Iowa) Globe Gazette reported.
The outdoor notice showed large photographs of the president, Nazi mass-murderer Hitler and Communist revolutionary Lenin beneath corresponding labels, "Democrat Socialism," "National Socialism" and "Marxist Socialism."
One Iowa Tea Party member said the billboard crossed a dangerous line.
"At our last rally we saw some people with these kinds of signs and asked people to put them down," John White, coordinator of the Iowa Tea Party movement said. "It's borderline hate crime."
Members of the North Iowa Tea Party either declined to speak or did not return calls to the newspaper Monday when the billboard was erected with the message underneath the three pictures saying, "radical leaders prey on the fearful & naive."