Library service in the Virgin Islands began in 1920 with the opening of the St. Thomas Public Library in rented quarters, using packing crates for shelves, wooden boxes and other odd pieces for furniture. A cooperative effort of the Junior Red Cross and the American Library Association with assistance from the U. S. Navy made the dream of a St. Thomas public library a reality. The first library director was Adeline Zachert, followed by Eleanor Gleason and Catherine Trimble. Libraries were quickly established on St. Croix at Christiansted and Fredericksted.

In 1929, the Carnegie Foundation granted $10,000 to extend library services in the islands and sent two trained continental Americans, Caroline L. Jones and Edith C. Moon to accomplish this task. Circulation increased 125 percent in St. Thomas, 150 percent in Fredericksted, and 340 percent in Christiansted. The Carnegie grants were renewed for two additional years. The libraries were referred to in Library Journal (15 Jan. 1943) as "modern in every respect...they follow the organizational pattern common in most American libraries."

The St. Thomas Library was moved in 1940 to the first and second floor of the former Lange Building. The building has also served as a Municipal Building and housed the Council of St. Thomas and St. John on the third floor. In 1943, the collection consisted of 20,000 volumes and the latest media was a Victrola for records and a silent 16mm projector. The "charge desk", locally made in 1935, was dedicated to Edna St. Vincent Millay, then in St. Thomas, to whom the first book was charged. That desk is still in use today.