The Harbor at Lorient was painted when Berthe Morisot visited her newly married sister, Edma Pontillon, in the summer of 1869. Edma was living in Lorient because her husband was a navy man and she did not yet have any children. Consequently the two women were free to spend their time visiting friends and painting outside. Berthe Morisot was experimenting with her painting method and working in a highly Impressionist style.
Edma was the subject of many of Morisot's portraits both before and after her marriage but since she had been married the two women had not spent a great deal of time together and must have missed each other terribly.
When Morisot returned to Passy with The Harbor at Lorient she anxiously showed it to her artist friends and colleagues. Her nervousness was ill-placed as her friends declared it one of her best works. It demonstrated Morisot's experimentation with different brush strokes, light and color and Manet admired it so much that Morisot gave it to him.
The Harbor at Lorient was so well-liked by Morisot's friends that it was displayed in the Impressionists first showcase. It is now housed in the National Gallery of Art in Washington DC.