The Detroit Free Press reports that many of the 14 billboards gave a September date for the election. The vote will actually take place Nov. 5.
City Clerk Janice Winfrey says the billboards were updated Saturday with information about the general election, and she calls the September date "a mistake" by the business that handles the billboards.
Winfrey says she noticed the error and was angry. Winfrey says she was told all the billboards would be fixed by Tuesday.
The November election includes races for Detroit mayor and city council.