About 2,500 customers were without service in Fairview Heights on Wednesday morning, including the Fairview Heights Police Department.
A post by the Fairview Heights Police said other township buildings were affected as well, and customers are reporting that power should be restored by about 11:45 a.m.
Ameren also reported the outages on its website.
The Police Department's power was restored by about 10 a.m., and phone calls and dispatching officers was not affected during the outage, an official said.
About another 1,00 customers were still without power around 10:10 a.m., according to Ameren.