Sandra Suh arrived at Beijing's Capital International Airport on a flight from Pyongyang, US embassy spokesman Nolan Barkhouse confirmed.
Asked for details on when Suh might return to the US, Barkhouse declined to comment.
Pyongyang's official KCNA news agency said yesterday that Suh had been a frequent visitor to North Korea over the past 20 years "under the pretence of humanitarianism".
She had "engaged in plot-breeding" and secretly taken photos and produced videos that had then been used as "propaganda abroad", KCNA said.
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KCNA said the decision to deport rather than detain her had been made "taking into full consideration her old age", without specifying how old she was.
Sandra Suh is registered as having founded a California- based organisation, Wheat Mission Ministries, in 1989, to provide food aid and medical technology to North Korea.
The organisation's website does not list Suh among its current staff and calls to its office in Los Angeles went unanswered.
Like a number of other humanitarian groups working in North Korea, Wheat Mission Ministries has a Christian grounding.