The Mary Lou Williams Collection is located at The Institute of Jazz Studies at Rutgers University in Newark, N.J. Since its opening in 2000, this Collection remains the single most used archival resource there. Ms. Williams saved almost everything. The 100 cubic feet of this archive contains numerous original music manuscripts, one of a kind sound recordings on acetates and tapes, a large number of photographs, her scrapbooks, her personal day-by-day books, her unpublished writings about music and her life, her paintings, and letters. This valuable collection at this prestigious Institute ensures that the life and work of Mary Lou Williams will continue to be known and safely extended in perpetuity.

The Mary Lou Williams Foundation Collection carries the archive from the date of Ms. Williams' death to the present. This collection contains transcribed musical works composed by Mary Lou Williams which are performance ready. These include: Big Band and Small Group scores and parts; Choral Works including Mary Lou's Mass; Zodiac Suite for Chamber Orchestra; and some Piano Works. This collection also possesses the complete catalog of CDs relating to the recorded music of Mary Lou Williams. Correspondence and ephemera fill out the story.