There is no completely clear answer to this question because there is no one exact methodology to measure and rate the partisan bias of news sources.
Here are a couple of resources that can help:
The more detailed report, The Political Gap in Americans' News Sources, examines news usage by political party. "In many cases, supporters of the two main U.S. political parties are relying largely on different sources of news and information." In general, Republicans have lower levels of trust in national news organizations than Democrats, with those levels steadily declining since 2016. However, Republicans' trust in national news organizations and social media sites has increased somewhat since 2024.
Here are a few examples of major news sources and their so-called "bias" based on ratings from AllSides and Media Bias/Fact Check (as of July 2025) and the reported level of trust from partisan audiences from the Pew Research Center.
Note that much of these ratings are based on surveys of personal perceptions. Consider that these may be impacted by the hostile media effect, wherein "partisans perceive media coverage as unfairly biased against their side" (source: Perloff, R. M. (2015). A three-decade retrospective on the hostile media effect. Mass Communication and Society, 18(6), 701-729. (U-M Library access)).
A consistent finding from the Pew surveys is that conservatives have a higher level of distrust overall of news sources and consume a narrower range of news sources. Left-leaning audiences trust and consume a broader range of news sources.
Therefore, there are more news sources that are rated or perceived as center-left/slight left leaning (especially mainstream sources); there are fewer news sources that are center-right. This represents the popular conservative discourse that the mainstream media has a liberal bias (and potential hostile media effect).
These news sources are rated as "Lean Left" by Allsides. According to the Pew survey, they are more distrusted than trusted by people who are mostly conservative and consistently conservative; and are more trusted than distrusted by people who are mixed, mostly liberal, and consistently liberal.
These news sources are rated as "Left" by Allsides. According to the Pew survey, they are more trusted than distrusted by people who are mostly liberal, consistently liberal; and are more distrusted than trusted by people who are mostly conservative, and consistently conservative.
These news sources are rated as "Lean Right" by Allsides. According to the Pew survey, they are more distrusted than trusted by people who are mostly liberal and consistently liberal; and are more trusted than distrusted by people who are mixed, mostly conservative, and consistently conservative. Note that this represents a further bias leaning than the "towards the left" sources. There are no direct parallels on the right.
These news sources are rated as "Right" by Allsides. According to the Pew survey, they are more distrusted than trusted by people who are mostly liberal, consistently liberal; and are more trusted than distrusted by people who are mostly conservative, and consistently conservative.