After the British took control of Kaskaskia, he became the commandant of Fort Sainte-Geneviève, in the Illinois Country for New Spain.

[1] Rocheblave was sent to Virginia, where he eluded parole and fled to the British forces in New York City.

According to Robert MacIntosh's 2006 book "Earliest Toronto", after the American Revolutionary War ended, Rocheblave first settled in Upper Canada, where Lord Dorchester, the Governor-General approved a grant of 1000 acres on the banks of the Humber River.

[2] However, the grant stalled when it fell to John Graves Simcoe, the Lieutenant Governor of Upper Canada, and his appointees, to process it, and specify the actual acres that should have been his.

In 1796, Rocheblave was elected to the Legislative Assembly of Lower Canada for Surrey and was re-elected in 1796 and 1800, serving until his death in 1802.