This series contains official papers acquired during William Dacres Adams' employment with the younger Pitt from 1783 to 1806, being the more numerous for the later years. The Portland papers cover the years 1807-1809.
Letters not strictly belonging to either secretaryship have been included under their respective years wherever they seem to have been received by Adams in virtue of his status as civil servant or private secretary. The private papers have thus been reduced to a minimum, and consist chiefly of family correspondence.