They had 12 children, including Jonathan Blanchard, a New Hampshire delegate to the Congress of the Confederation in 1784.
At the start of the French and Indian War, Joseph Blanchard was already a colonel in the militia, and in 1754 he ordered Capt.
In 1755, Joseph Blanchard was appointed as Colonel of the New Hampshire Provincial Regiment sent to serve under Sir William Johnson in an attack on Crown Point on Lake Champlain.
Along the march they built Fort Wentworth at Northumberland, New Hampshire on the Connecticut River.
In 1761, a new more accurate map of New Hampshire that Joseph Blanchard had prepared in connection with Samuel Langdon was published.