Ferde Grofe donated his 1924 orchestration of Rhapsody in Blue to the Library of Congress. Here is an account from the LOC website.
On July 1, 1946, the Library of Congress was privileged to extend a welcome to the distinguished composer and conductor, Ferde Grofé. His appearance at the Library would have been notable on any occasion, but it was remarkably so on this one, for he brought with him as a gift to the Library his original manuscript of George Gershwin's famous Rhapsody in Blue, an epoch-marking work in the annals of American music.
The first public performance of the celebrated Rhapsody occurred at Aeolian Hall, New York, on February 12, 1924. Gershwin played the solo piano part with Paul Whiteman's orchestra (Whiteman conducting) supplying the accompaniment as it had been scored by Grofé. The printed program of the concert bore the legend "An experiment in modern music," and it was aptly named. Although the occasion was not the first time that jazz music had been heard in the sacred precincts of polite concert halls, it was quite unprecedented with regard to scope, careful planning, and seriousness of purpose. The success of the venture was sensational; its effect was permanent. And much of the influence of jazz music on "art" music dates back to that concert.
The brightest feature of the program was undoubtedly Gershwin's Rhapsody. The composer was far from unknown before the event, but musician and layman alike were uncertain of what he could do with jazz idioms in one of the larger forms of composition. A remarkable pianist himself, Gershwin was asked by Whiteman to attempt the medium of the piano concerto. He was then only twenty-six years old and less familiar with orchestral and jazz-band scoring than he subsequently became. Consequently Grofé, who had been with Paul Whiteman's organization since 1920, accepted the task of orchestrating the accompaniment for the much-anticipated performance. The success of Grofé's work was likewise overwhelming, and the original features of the Rhapsody's instrumentation are practically as famous (and as influential) as the music written by Gershwin.
The autograph score received by the Library of Congress is the one made by Grofé in the course of orchestrating the Rhapsody. Except for the extended solo piano passages and the cadenzas, which were written down by a copyist, it is all in Grofé's hand and constitutes one of the most important manuscripts in the Library's collection of musical holographs. It consists of thirty-one leaves, the last two blank, measuring 13 ˝ by 10 ˝ inches. The changes from one instrument to another, the special technics of jazz playing, the devices for percussion effects, the solo treatment of woods and brasses are all clearly indicated, and the genius of the orchestrator shines forth from every page. Grofé became, in his own right, one of America's most eminent composers, universally acknowledged for his imagination and originality in instrumental combinations. He enjoyed a long creative career. Yet his early association with Gershwin's Rhapsody in Blue is of first importance, too, and the manuscript he presented to the Library, which now resides in the Ferde Grofé Collection, is a document of lasting significance.