Excerpts from wrex.com:

Thirty firefighters, five Rockford fire engines, and three ladders responded to a nearly 150-year-old abandoned church fire Wednesday night at 607 Walnut St., at 6:24 p.m., and quickly spread because of the wooden structure. The church has been abandoned for several years. Rockford Fire Chief Derek Bergsten said he anticipates Kishwaukee and Walnut streets to be closed until morning.

A cause of the fire is still unknown. There was no power to the church, which rules out an electrical issue. Investigators interviewed neighbors and ask the public for any information on how the fire started.

According to inscriptions on the church, it was formerly the Rockford Masonic Cathedral. The year 1869 was etched into one of its walls. At one point it became the Metro Christian Center.