The will of Susan Cornelia Warren (1825-1901) established a trust in memory of her husband, Samuel Dennis Warren. Although Mrs. Warren died in 1901, action on the trust did not commence until September 1927, beginning with a generous bequest of $130,000. In her will, Susan expressly provided that the benevolent purposes which she had in mind might be executed by a charitable corporation, succeeding the trustees named in her will. The trust fund was to create a permanent foundation for educational purposes. Since Susan had a love for the arts, it also included the cultivation and promotion of the fine arts. Susan left the bequest to the mill library in her will, stating that the funds would be administered by her daughter Cornelia and her son, Edward Perry, a college professor, until their deaths, when a board of trustees would be chosen to carry on.

The original library, called Cumberland Mills Library, was established in 1876, for mill employees and their families. Books were housed in a room above the Mill Agent's office. The mill library then moved to the present building, owned by the S.D. Warren Company. On October 24, 1927, the Warren Company Board of Directors voted to turn over the mill library to the trustees, with the understanding that they would accept title and responsibility. On November 1, 1929, the Warren Memorial Foundation was established, and the mill library was officially opened to the public. It is now called the Warren Memorial Library. On September 8, 1927, Edward Perry Warren, Robert Hale, and Nelson R. Davis, the original three trustees, met at Mr. Warren's Fewacres Estate in Gorham and voted to withdraw all the funds of the trust as soon as possible after January 1, 1928. At the time, the assets were being held in an interest-bearing savings account by the S.D. Warren Company. Two months later, the trustees withdrew $129,838.84 and promptly invested it in bonds having a par value of $126,000.