An estimated 16.4 million people paid one last visit to the “ER” on Thursday, as the final piece of NBC’s once-mighty “must-see TV” lineup signed off after 15 years.

It was the biggest audience for a drama series finale since “Murder, She Wrote” on CBS in 1996, Nielsen Media Research said Friday.

The two-hour finale brought back vintage “ER” stars Noah Wyle, Eriq La Salle and Laura Innes alongside current cast members John Stamos and Angela Bassett.

It was a typical few days at Chicago’s mythical County General Hospital – a woman who dies in childbirth, an AIDS patient who learns he has cancer – ending on a hopeful note: The 22-year-old daughter of Anthony Edwards’ character, Dr. Mark Greene, is enthralled by the action and wants to be an emergency room doctor.

Thursday night’s audience was up sharply from the 9.5 million people who watched on an average week this season, but it’s still half as many people who watched “ER” at its peak in the mid-1990s.

When “Cheers” exited the NBC Thursday night lineup in 1993, there were 45.5 million people watching. The end of “Seinfeld” drew 41.3 million people in 1998.

“Friends,” the last big piece of NBC’s previous Thursday schedule, had 29.2 million viewers for its 2004 finale.