Broad agreement in U.S. – even among partisans – on which news outlets are part of the ‘mainstream media’
Pew Research Center From the Center

The term “mainstream media” has long been used to refer to established journalism outlets in the United States. In recent years, it has also been used in a more critical context, including by former President Donald Trump, other politicians and members of the media themselves.
To learn more about how Americans think about the term, Pew Research Center asked a representative sample of U.S. adults whether they consider each of 13 different news outlets to be a part of the mainstream media or not. The outlets were selected to represent a range of audience sizes and sectors.