National Museum of American History (Smithsonian), Washington, DC.
writing box was designed by Jefferson and built for him in May 1776 by Philadelphia cabinetmaker Benjamin Randolph. Among it's first uses was the writing of the Declaration of Independence, which he composed in June, while serving in Continental Congress.
Jefferson used this laptop desk throughout his life. It has a locking drawer on the side for paper, pens, and inkwell. The adjustable bookrest is double-hinged; it folds out to provide an extended surface for writing.