"In 1806 and 1807 there was much disquiet at Detroit on this account, and a new stockade was built as a protective measure."
Note: The British, some of whom were just across the river in Canada, had aspirations of reacquiring Detroit, territory that had been ceded to the Americans after the Revolutionary War.
The new stockade was built by Governor Hull and encompassed all of the grounds between the Cass and Brush Farms and extended to the fort. There were gates and blockhouses on each side at Jefferson Avenue.
From The Early History of Michigan....
The eastern boundary of this stockade was along the eastern line of the Brush farm about where Brush street now runs. There was a gate on Atwater street near the present Pontiac depot and a blockhouse on Jefferson Avenue a few rods east of the present site of the Biddle House. The western line of the stockade ran along the eastern line of the Cass farm then known as the Macomb farm and the western gate was on Jefferson Avenue about one hundred feet below Cass street. The northern line ran about in range with the fort.
In the spring of 1827 the stockade was removed and Fort Shelby was demolished.