This material documents the estate of Mrs. Charlotte Frobisher and includes a copy of her will and an inventory, 1820.

The collection consists of 10 ink manuscript maps and plans on paper, some hand-coloured, depicting the earliest settlements and fortifications at Montreal and Quebec City. The earliest dated document is a plan of the fort of Quebec and is dated 1635. The earliest document in the collection depicting Montreal is believed to date back to 1642. The maps and plans were prepared by Jean Bourdon, seigneur and surveyor for the French colony. Included in the collection is a plan of the earliest Fort Richelieu of which nothing had previously been known. There are also detail drawings of riverside fortifications, probably near Montreal.