According to the Reporters Without Borders index, the U.S. ranks 45 (out of 180) in 2018, just behind Romania and South Korea. Here is what they have to say about the U.S.
US press freedom, enshrined in the First Amendment to the 1787 constitution, has been under increasing attack over the past few years, and the first year of President Donald J. Trump’s presidency has fostered further decline in journalists’ right to report. He has declared the press an “enemy of the American people” in a series of verbal attacks toward journalists, attempted to block White House access to multiple media outlets, and routinely uses the term “fake news” in retaliation for critical reporting. He has even called for revoking certain media outlets’ broadcasting licenses. The violent anti-press rhetoric from the highest level of the US government has been coupled with an increase in the number of press freedom violations at the local level as journalists run the risk of arrest for covering protests or simply attempting to ask public officials questions. Reporters have even been subject to physical assault while on the job. It appears the Trump effect has only amplified the disappointing press freedom climate that predated his presidency. Whistleblowers face prosecution under the Espionage Act if they leak information of public interest to the press, while there is still no federal “shield law” guaranteeing reporters’ right to protect their sources. Journalists and their devices continue to be searched at the US border, while some foreign journalists are still denied entry into the US after covering sensitive topics like Colombia’s FARC or Kurdistan.
You can download their data and since the rankings stared in 2002 you might be able to get access to past data (some of it is available in their archives). Their methodology is explained and they have an interactive map.