Cook County vs. State Law:
Navigating Local Firearms Ordinances

Cook County occupies a unique position in Illinois firearms law. As a home-rule unit under the Illinois Constitution, Cook County has authority to enact firearms ordinances that go beyond state requirements. For the roughly 5.2 million residents of Cook County, this creates a layered regulatory environment where compliance with state law alone may not be sufficient.^[1]

Cook County's Home-Rule Authority

Article VII, Section 6 of the Illinois Constitution grants home-rule powers to any municipality with a population over 25,000, as well as to Cook County itself. Home-rule units may "exercise any power and perform any function pertaining to [their] government and affairs," unless the General Assembly specifically preempts that authority. Because the Illinois General Assembly has not fully preempted local firearms regulation, Cook County retains broad authority to enact firearms ordinances that are more restrictive than state law.^[1]

The Blair Holt Assault Weapons Ban

Cook County's most significant firearms ordinance is the Blair Holt Assault Weapons Ban, which bans the possession, sale, and manufacture of assault weapons within unincorporated Cook County and within municipalities that have not enacted their own ordinances on the subject. The Cook County ban predates the state's Protect Illinois Communities Act (Public Act 102-1116) and is in some respects broader than the state ban. While the state ban took effect on January 10, 2023, the Cook County ordinance has been in place since 2006 and covers categories of weapons and features that may differ from the state's definitions.^[2]

The interaction between the Cook County ban and the state ban creates complexity for residents. In areas where both apply, a firearm owner must comply with whichever law is more restrictive. A firearm that is legal under the state ban may still be prohibited under the Cook County ordinance if it falls within Cook County's broader definition of an assault weapon.

Municipal Ordinances Within Cook County

Several municipalities within Cook County have enacted their own assault weapons ordinances, which supersede the county-level ban within their jurisdictions. These municipalities include Buffalo Grove, Dolton, Evanston, Hazel Crest, Homewood, Lincolnwood, Riverdale, and Skokie.^[2] Each of these municipal ordinances may define "assault weapon" differently and impose different penalties for violations. A firearm owner who moves between municipalities within Cook County may need to verify compliance with each jurisdiction's specific ordinance.

Chicago's Firearms Ordinances

Chicago maintains its own firearms regulatory framework that is distinct from both Cook County's ordinances and state law. Chicago's ordinances include firearm registration requirements that predate the 2013 state preemption law and have been grandfathered under the Firearm Concealed Carry Act's preemption provisions. Chicago residents must comply with city-level ordinances in addition to Cook County and state-level requirements, creating a three-layer regulatory framework.^[1]

Practical Implications for Cook County Residents

The layered regulatory environment in Cook County creates several practical challenges for firearm owners:

• Compliance with multiple laws: A Cook County resident must comply with federal law, Illinois state law, the Cook County ordinance, and potentially a municipal ordinance -- all simultaneously. In every case, the most restrictive provision controls.
• Transport across jurisdictions: A firearm that is legal in one Cook County municipality may be prohibited in another. When transporting firearms, owners should verify the laws of each jurisdiction they pass through.
• Assault weapons definitions: The Cook County ban, the state ban, and individual municipal bans may each define "assault weapon" differently. A firearm that is not classified as an assault weapon under one definition may be classified as one under another.
• Grandfathering provisions: The state's grandfathering provision under the Protect Illinois Communities Act does not automatically ensure compliance with Cook County's separate grandfathering rules, which may differ in scope and deadlines.

Firearm owners in Cook County should consult the specific ordinances applicable to their municipality of residence and any municipalities they regularly travel through. The Cook County ordinance applies as the default in unincorporated areas and in municipalities that have not enacted their own assault weapons ordinances.^[2]

State Preemption Limitations

The Firearm Concealed Carry Act (430 ILCS 66/90) includes a partial preemption clause that prevents home-rule units from regulating the carrying of concealed firearms in a manner inconsistent with the Act. However, this preemption is narrow -- it applies specifically to concealed carry regulation and does not extend to other areas of firearms law such as assault weapons bans, registration requirements, or taxation. This limited preemption is what allows Cook County and its municipalities to maintain firearms regulations that exceed state standards in many areas.^[3]