Cusack, Gilfillan & O'Day (CGO) was founded by Peoria attorney Dan Cusack on April 1, 1984.  Joe Gilfillan and Dan O'Day joined the firm several years later and became partners in 1991.

The firm, consisting of four attorneys, operates a general practice of law, with each partner and associate concentrating in specific areas of practice.  Cusack, Gilfillan & O'Day advises and represents both individuals and businesses.  Emphasis is on such areas as personal injury, workers' compensation, family law, real estate, civil litigation, criminal law, appeals, estate planning, probate, businesses, and employment litigation.

The attorneys of Cusack, Gilfillan & O'Day have appeared in circuit courts throughout most of the State.  However, with our offices located in 415 Hamilton Blvd., the majority of the firm's work is in Central Illinois.  The firm's attorneys regularly appear in court in Peoria, Tazewell, Woodford, Marshall, Putnam, Stark, Knox, Fulton and McLean Counties.  They also appear with some frequency in Counties such as Warren, Henry, Mason, Livingston, and McDonough.

Cusack, Gilfillan & O'Day attorneys are admitted in Federal Courts in Illinois, and often appear in State and Federal courts of review including the Illinois Appellate and Supreme Courts.

As of 2004, the attorneys of Cusack, Gilfillan & O'Day have a total of over 125 years of experience practicing law in Central Illinois.  Our firm has represented thousands of clients.