Division 4 - Matthew Thornhill

Judge Matthew Thornhill was born in Saint Charles, and he has lived in Saint Charles County his entire life. His mom, Rita Thornhill, still lives in his childhood home in O'Fallon. He has five brothers (one, Andrew, deceased) and one sister. Two of his brothers, Kenny and David still live in the county. Matthew attended Assumption Grade School and Saint Dominic High School, where he graduated in 1986. He went on to Rockhurst College in Kansas City and Notre Dame Law School in Indiana.

In 1993, Judge Thornhill began his legal career as an assistant prosecutor for Saint Charles County, and he spent the next thirteen years there. He litigated sixty-five jury trials, first in traffic court and later in the felony division and sex crimes unit. He received MADD's Prosecutor of the Year Award, as well as the largest verdict in the county's history, sixteen life sentences for a child predator, in 1999.

He was elected Associate Circuit Judge in 2006, where he served the county in Division 12 for eighteen years. In 2024, he was elected Circuit Judge in Division 4. No other judge has served Saint Charles County longer than him! He has presided in more than twenty-five jury trials, both civil and criminal, and thousands of bench trials in civil, criminal, and family cases, including small claims, orders of protection, and Department of Revenue trials de novo. His current assignment includes criminal, civil, and juvenile matters, as well as conflict cases from other circuits.

Matthew married his wife Heather in 1997, and they have seven children together, six girls and one boy. Judge Thornhill loves Elvis, surfing, gardening, watching soccer, golfing with his children, and running with his dog on the Katy Trail. He also keeps bees, plays pickleball with his kids, and frequents thrift stores looking for old books, bow ties, and Converse shoes. You can often find him at Allin's Diner on Kingshighway in Saint Charles, ordering a hamburger and coffee for lunch.