The plane took off from Cincinnati Municipal Lunken Airport Saturday at 10:11 a.m. and landed at Washington Dulles International Airport just after midnight, the Solar Impulse blog reported.
Fog in Cincinnati caused some concern, but the ground crew used cloths and pipettes to wipe off condensation from the wings, the blog said.
Solar Impulse co-founders Andre Borschberg and Bertrand Piccard have been alternating pilot duties on the cross-country trek.
Saturday's flight was Piccard's last mission flight, the Solar Impulse blog said.
The first leg, beginning May 3 and piloted by Piccard, started from NASA's Moffett Field in the San Francisco Bay Area and ended in Phoenix; a Phoenix-to-Dallas flight with Borschberg at the controls began May 22.
The long flight times of each leg meant Solar Impulse had to fly through the night; 12,000 solar cells built into the wing use sunlight to charge the batteries for night flight.
The final leg of the trek will end in New York in early July.