Mariah Carey, The Queen Of Christmas, Visits White House -

Gallery Launch Gallery Mariah and Biden Do Xmas! Launch Gallery

Mariah Carey's reign as the Queen of Xmas is only getting stronger ... as she journeyed to D.C. to spread some festive cheer at the White House.

In a post shared to her IG Wednesday, the singer posed with President Joe Biden ... with her 12-year-old twins Moroccan and Monroe in tow.

Wearing a glittering minidress and matching cropped jacket for some extra Christmas flare, Mariah was in her element as she also got snap-happy with Kamala Harris & her hubby Doug Emhoff.

In the caption, Mariah gushed about all the extensive festive decor she saw during the visit ... which took place last week with her brood.

CALLIN' IT QUITS

The twins have been popping up a lot lately in their momma's Christmas-related ventures ... most recently in the music vid for the upgraded version of her classic, "All I Want For Christmas Is You."

Gallery Launch Gallery Mariah's Christmas Photos Launch Gallery

For years now, Mariah's been committed to making the run-up to Christmas special -- but with her festive tour wrapping on Dec. 17 ... we're hoping she has the day itself to unwind.