An Irish joiner naturalized in Philadelphia, John Neilson worked at Monticello from 1804 to 1809.  Neilson worked with James Dinsmore  on the construction of Monticello II (1796-1809).  Jefferson wrote that “they [Neilson and Dinsmore] have done the whole of that work in my house, to which I can affirm there is nothing superior in the U.S.” Neilson and Dinsmore trained the enslaved John Hemmings as a joiner who took over for them when they left.  In 1809, “Dinsmore and Neilson set out … for Montpelier;” and continued to work together for several years, both returning to Charlottesville to help construct the University of Virginia.  Jefferson described Neilson as “a gardener by nature, & extremely attached to it.” Neilson died in 1827, by which time he owned a considerable estate in Charlottesville, including 11 enslaved individuals.