Dan opened Cornerstone in 2001 with a folding card table, a phone, and twenty-eight clients. Karen joined six months later. Sarah passed her P&C exam this April.
FounderDaniel Mercer
Daniel Mercer grew up on a dairy farm two miles east of Hanover. He spent fifteen years at State Farm — Galena office, then Freeport, then Galena again — before walking out in the spring of 2001 to start something he could run his own way. The State Farm job paid well. He liked his colleagues. The problem was the policy: when the company decided to non-renew a fifteen-year customer over one minor at-fault claim, he had no answer except "I'm sorry, that's our underwriting." That wasn't a job he wanted to do anymore.
The first Cornerstone office was a 320-square-foot upstairs room above what is now the Galena Cellars Vineyard tasting room. Dan had a card table, a corded phone, and twenty-eight clients who had followed him out the door. Eight months later, he and Karen signed a five-year lease on the storefront at 215 South Main where the agency still operates. The building was originally a hardware store. The pressed-tin ceiling is still there.
Dan is a past president of the Galena Rotary Club and currently sits on the Board. He spent the 2008 storm season — the year the spring floods took out twelve basements and a barn within four miles of the agency — driving from claim site to claim site for two months straight, helping clients photograph damage and walk adjusters through what they were seeing. That summer taught him what claims advocacy actually looks like. It's a lesson the website tries to live by.
He answers the phone himself, on his cell, after hours. He's done it for twenty-five years and he isn't going to stop now.
Client ServiceKaren Mercer
Karen Mercer joined Cornerstone in the fall of 2001, six months after Dan opened the doors. She has handled the back-office work — billing, certificates of insurance, mid-term endorsements, renewals, claims paperwork — every working day since. If you have ever wondered how a small agency keeps everything organized, the answer is: Karen.
Most of our clients know her by first name. She grew up in town. Her kids went to Galena schools with our clients' kids. She remembers who married into which family, whose driveway flooded in 2014, and which household has the teenager whose first car needs to be added to the policy this fall. None of that is on a computer. It's in her head.
Karen's Friday-morning check-in routine — phone the eight or ten households whose renewals are coming up in the next three weeks, ask them what's changed, see if there are gaps — is the reason our retention rate stays above ninety-three percent.
ProducerSarah Mercer
Sarah Mercer, age 26, grew up sweeping the agency floors on Saturday mornings and graduated from Northern Illinois University in 2022 with a degree in accounting. She worked two years at a Rockford CPA firm before deciding she wanted to come home. She passed her Illinois Property & Casualty licensing exam in April 2026 and joined Cornerstone as the agency's second producer the following month.
Sarah handles new-business intake and is steadily taking over Dan's auto book, freeing him to focus on home and umbrella work. If you call the agency in the mornings the next twelve months and Dan is in a meeting, you are probably talking to Sarah — and she is the future of the agency.
"We've never been the cheapest. We're sometimes ten percent more than the GEICO quote on your phone. Every year a few people leave for the savings. Every two or three years a few of them come back when they have a claim and discover that the savings disappeared." — Dan Mercer