How do Chicago police identify immigration status among arrestees?

1. What the law and city policy explicitly bar: CPD cannot act as ICE’s field office

Chicago’s Welcoming City Ordinance and subsequent guidance make clear that Chicago Police Department officers “will not detain, arrest, or assist ICE based on civil immigration violations, detainers, or administrative warrants,” and they are prohibited from asking about immigration status in routine policing and city forms ^{[3] [2]}. The ordinance requires CPD to file quarterly reports listing any notifications made when federal agencies request assistance with civil immigration enforcement — an accountability mechanism showing the city expects to be insulated from routine federal immigration activity ^[2].

2. How CPD typically handles identification during arrests: focus on criminal law, not immigration paperwork

CPD training and policy materials emphasize that officers are trained to enforce Illinois and Chicago law, not federal immigration statutes, and that the department provides service regardless of citizenship status ^{[6] [3]}. Multiple local outlets and the city state that CPD “does not document immigration status and does not share such information with federal authorities,” reflecting the department’s operational stance to avoid using immigration status as a policing trigger ^{[7] [1]}.

3. When CPD can lawfully act on immigration-related matters: narrow exceptions exist

Local and state rules are not absolute blocks: city and state law recognize that CPD must comply with statutory or court-ordered requirements, and Illinois guidance from the attorney general clarifies that local agencies cannot participate in federal civil immigration enforcement unless federal agents have a criminal warrant or federal law specifically requires it ^{[8] [5]}. In practice that means if a judicial warrant or a specific statutory mandate exists, CPD’s hands may be tied differently than in routine encounters ^[5].

4. Federal operations in Chicago and where friction shows up

Recent large-scale federal raids in Chicago led to hundreds of arrests, and federal agents operated in neighborhoods while CPD’s role was constrained by city policy — producing visible friction between local noncooperation policies and federal enforcement actions ^{[9] [10] [11]}. Court actions tied to those raids — for example litigation seeking releases and limits on how detainees can be handled — underline that federal enforcement can occur even when local agencies decline to assist, and that federal vetting and detention decisions remain federal prerogatives ^{[9] [10]}.

5. Practical indicators officers might use (and limitations in reporting)

Available CPD materials and city guidance emphasize that officers respond to declarations (e.g., if an arrestee says they are a foreign national) and certain custody procedures (consular access) may be triggered when foreign-national status is known, but they avoid proactive documentation of immigration status in records or forms ^{[6] [3]}. However, the publicly available sources do not provide a line-by-line checklist of exactly what identification steps a patrol officer takes in the field beyond these general principles — they emphasize prohibition on asking about status rather than enumerate every permitted data point ^{[3] [6]}.

6. Oversight, reporting and political context that shape practice

City requirements to report requests from federal agencies, mayoral executive orders denouncing militarized immigration enforcement, and state attorney general guidance create layers of policy that constrain CPD actions and require transparency around interactions with federal enforcement ^{[2] [4] [5]}. These policies are politically charged: proponents argue they protect community trust and public safety, while critics — and some federal officials — have argued sanctuary policies impede federal enforcement, a dispute reflected in litigation and public debate surrounding recent raids ^{[12] [9]}.

7. What the sources do not say (important gaps)

Available sources do not provide an operational, officer-level checklist for how CPD verifies identity versus immigration status at booking, nor do they publish detailed internal decision trees for when an officer must escalate a federal request beyond the quarterly reporting requirement (not found in current reporting). Also, while city materials say CPD “does not document immigration status,” the exact mechanics of data fields in arrest or booking systems and any limited exceptions are not fully detailed in the cited documents ^{[3] [7]}.

8. Bottom line for residents and advocates

For most encounters CPD’s written policy and city/state directives mean officers will not ask, document, or act on civil immigration status alone and will not cooperate with ICE absent judicial or statutory compulsion — and the city tracks and reports federal requests for assistance ^{[1] [2] [5]}. Still, federal agents retain authority to arrest under federal law, and recent raids in Chicago show those operations can proceed without CPD participation, prompting litigation and heightened community concern ^{[10] [9] [11]}.