Process Serving in Illinois

Illinois civil cases are filed in the circuit courts, the state’s trial courts of original jurisdiction, organized into 25 circuits. Appeals generally go to the Appellate Court district for that circuit; some cases may reach the Illinois Supreme Court directly or by petition for review.

Service is ordinarily made by a sheriff or coroner, but Illinois law also authorizes licensed or registered private detectives and registered employees of certified private detective agencies to serve process without a special court appointment. A court may also appoint a private person over 18 who is not a party. Court Runner USA connects you with process servers who serve papers across Illinois.

General information, not legal advice. Last checked October 2026.

Sources:

• Illinois Courts — How cases proceed
• 735 ILCS 5/2-202
• IDFPR — Private Detective

Illinois process may be served by a sheriff or, if the sheriff is disqualified, by a coroner of an Illinois county. A sheriff in a county with fewer than 2 million residents may employ civilian personnel to serve process.

State law also permits service without special appointment by a person licensed or registered as a private detective under Illinois law, or by a registered employee of a certified private detective agency. The detective or agency must give a copy of the license or certificate to the sheriff of each county where it serves process, and the agency must keep a list of its registered employees (735 ILCS 5/2-202).

On motion, a judge may appoint a private person over 18 who is not a party to the case to serve process. The statute has a separate special-appointment provision for a limited category of eviction proceedings. The Illinois Department of Financial and Professional Regulation (IDFPR) licenses private detectives and private detective agencies.

Sources:

• 735 ILCS 5/2-202
• Private Detective Act, 225 ILCS 447
• IDFPR — Private Detective

For an individual, Illinois law allows personal delivery of the summons, or abode service: leaving it at the person’s usual place of abode with a family member or resident aged 13 or older, telling that person what it contains, and mailing another copy to the abode in a sealed, postage-paid envelope (735 ILCS 5/2-203).

A private corporation may be served by leaving process with its registered agent or with any officer or agent of the corporation found anywhere in Illinois (735 ILCS 5/2-204). Separate provisions cover partnerships and public corporations.

Where the ordinary methods are impractical for an individual, the plaintiff may ask the court to order a comparable method consistent with due process; the motion must describe the investigation and the reasonable efforts that failed (735 ILCS 5/2-203.1). Publication is available in qualifying actions affecting property or status, after a supporting affidavit and the required publication and mailing steps (735 ILCS 5/2-206). The Code also provides a narrow Secretary of State route in certain product-liability actions against defendants located outside the United States, and a written waiver of service is another statutory option.

Sources:

• 735 ILCS 5/2-203
• 735 ILCS 5/2-203.1
• 735 ILCS 5/2-204 and 2-206
• 735 ILCS 5/2-209(e)
• 735 ILCS 5/2-213

The standard Illinois summons requires a defendant to answer or otherwise appear within 30 days after service, not counting the day of service; the summons form and its requirements are governed by Supreme Court Rule 101.

Illinois sets no fixed number of days for service after filing. Instead, Rule 103(b) permits dismissal if the plaintiff fails to use reasonable diligence to obtain service before the applicable limitations period expires. The court looks at all the circumstances, including the history of any earlier case and the diligence shown after refiling.

For service outside Illinois, at least 30 days must pass after service before a default may be entered. Publication notice must run at least once a week for three weeks in a row, with the first publication at least 30 days before a default or other proceeding. The summons and the case type control the specific response date.

Sources:

• Illinois Supreme Court Rule 101
• Illinois Supreme Court Rule 103
• 735 ILCS 5/2-207
• 735 ILCS 5/2-208

A private person serving ordinary process must be over 18 and not a party to the action. To serve without a case-specific appointment, the server must meet Illinois’s private detective licensing or registered-employee requirements.

Abode service has specific safeguards: the recipient must be a family member or resident at least 13 years old, must be told what the papers contain, and an additional copy must be mailed to the usual abode.

Illinois law directs employees of specified licensed care facilities not to obstruct proper service, and requires employees of gated residential communities to let an authorized process server in to serve a defendant or witness who lives, or is known to be, in the community. Special procedures apply to serving people who are incarcerated, including arrangements with the facility’s representative.

Sources:

• 735 ILCS 5/2-202
• 735 ILCS 5/2-203
• 735 ILCS 5/2-203.2

When a sheriff or coroner serves process, that officer endorses the return. When a private person serves, the return is made by affidavit. For abode service, the certificate or affidavit must identify the person the summons was left with by sex, race, and approximate age, and state where, when, and at what time it was left; the server must also account for the required follow-up mailing (735 ILCS 5/2-202, 2-203).

Illinois Supreme Court Rule 102 governs the return of the summons and complaint and the information recorded about service. Section 1-109 of the Code allows a certification under penalty of perjury to be used in place of a sworn document unless a Supreme Court rule expressly requires otherwise. A court order may set the proof required for a court-directed alternative method.

Sources:

• 735 ILCS 5/2-202
• 735 ILCS 5/2-203
• Illinois Supreme Court Rule 102
• 735 ILCS 5/1-109