In 1917, the school moved to a campus located on Nebraska Avenue. Mrs. Somers, although retired, remained active in the operation of the school. She sold her M Street property to the
YWCA, in keeping with her dedication to educating girls and young women.
World War I forced students to quickly become involved in war efforts such as organizing First Aid classes and rolling bandages for wounded soldiers. The Seminary was assigned a ward at Walter Reed Hospital and students made care packages for hospitalized soldiers. Of the 20 graduates in the class of 1920, eight continued their education at four year colleges including
University of Wisconsin,
Northwestern University,
University of Montana,
Stanford University, and
University of Texas. This was not common practice for women at the time, and testified to the solid education they received while at the Seminary. By 1923, graduates were attending
University of California at Berkeley,
Columbia University,
Stanford University,
Cornell University,
Smith College,
Wellesley College and
The University of Chicago. In 1923, Adelia Gates Hensley died, and one year later, Elizabeth Somers. Although Mrs. Somers was the founder of the school, Mrs. Hensley had seen the school through a period of tremendous growth, and is credited with substantially improving the faculty. She was replaced by Jean Dean Cole, a former Seminary student and
Mount Holyoke College graduate. Under her leadership, the school established a Junior College as a separate unit. Mount Vernon Seminary and Junior College operated together, but with a clear distinction between the two—the four year preparatory school and the two year junior college section. Until that time, students had to study for a complete six years before receiving a diploma. In 1936, Jean Dean Cole resigned. Mr. George Lloyd became the fourth president of the college and his wife, Mrs. Olwen Lloyd became Headmistress in 1938. During
World War II, volunteer war work became a part of life at Mount Vernon, with students participating in air raid drills, nurses' aid training, and
Red Cross work. In 1942, the
United States Navy informed Mr. and Mrs. Lloyd that they planned to take over the Nebraska Avenue campus and use its facilities for the war effort; to be called the
Naval Communications Annex for intelligence work. Students went home for Christmas break not knowing if their school would re-open after the holidays. The board of trustees began searching for a new location for the school. The Nebraska Avenue campus was listed on the
National Register of Historic Places in 2016. ==Spring Valley, 1943–1946==