Police had appealed for help in locating Fatuma Kadir, missing after leaving her home in Bolton on Thursday evening.
She was found in London on Saturday and will now be reunited with her family.
Chief Detective Inspector Paul Rollinson of Greater Manchester Police said: “We are delighted to confirm that Fatuma Kadir has been found safe and sound.
“She was found in London earlier today, so we are now working to reunite her with her parents, who are, as you can imagine, incredibly relieved.
“The past two days have been every parent’s worst nightmare so I know they will agree with me when I say a big thank you to everyone who shared our call to find Fatuma. Your help has been invaluable, so thank you.
“We would now like to ask that their privacy be respected, so that they can be together as a family. “
Fatuma’s parents, Asheem and Misra Kadir, said they were in a “state of shock” after the 11-year-old went missing.
They had reported his disappearance just before 10:45 p.m. on Thursday, July 22.
The investigation revealed that Fatuma boarded a train from Manchester Piccadilly to Birmingham New Street at 9:27 p.m. that evening.
She then took another train to London Euston, arriving at 1:13 a.m. on Friday, and was last seen leaving the station alone a few minutes later.
Police said Fatuma had informed his two best friends or family of any plans to travel to London.
However, she had previously expressed ambition to start a clothing business in Tower Bridge, agents said.