Eighteen years after the Independent School District of Boise City was chartered in 1881, the School Board passed a resolution which stated that a new school building was needed in the north part of town. The date was May 26, 1899. W. E. Pierce donated the west one half of Block 10 in the Brumback Addition for the four room brick school that was eventually built at a cost of $5,000, including the building, equipment and furniture. On February 19, 1900, Washington School first opened its doors under Principal Loda L. Bellville and two teachers, Miss Jeanette Tomlinson and Miss Margaret B. Thomas. Although only two rooms were needed at first, by the 1900-01 term, all four rooms were in use. Tuition was 25 cents a week, and on January 13, 1902, several students were suspended for not paying.

Growing pains continued as only two years after Washington's opening, the School Board discussed an addition in the March 6, 1902 meeting. Eventually, the bond issue passed and school opened with seven teachers and six grades in September of 1903. The average teacher load varied from 36 to 42.

On March 9, 1908, the School Board purchased the east one half of Block 10 of the Brumback Addition, giving Washington School a full block. On approximately June 3, 1917, a fire swept through the old building, reducing the size of the school to one building of eight rooms, grades 1-6. Finally, on October 18, 1946, a contract of $125,180 was awarded for a four room addition. By 1947, the facility had twelve rooms, an auditorium and stage, and modern restrooms on the first and second floors.