The patio on 14th & Madison st NW where you will enter the museum. It's an out door eating spot.
They can wait outside the public entrances on the south and north sides of the building, which may be tbe outside spots mentioned in other replies, but it may not be comfortable to do so in cold/rain/snow/extreme heat. It was very cold outside the day we visited so I and my adult children showed our tickets and entered earlier than the time listed on our tickets and chose to wait indoors while my husband parked the car a few blocks away and walked back to join us inside to begin our tour of the museum. Phenomenal experience I will be going back again and again!
Constitution Ave
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