These records consist of letters, petitions, accounts and other legal documents received by the Civil Secretary of Upper Canada from 1791-1841, along with copies of some documents from 1766-1809.
They are a "mixed bag" of items, often worth checking, because you never know what you might find here.
Resources
Microfilms
Upper Canada Sundries, 1766-1841
No index or keyword-searching, but you can browse the digitized microfilm images page by page.