Illinois licenses day care centers under 89 Illinois Administrative Code Part 407 — Licensing Standards for Day Care Centers, authorized by the Child Care Act of 1969 and enforced by the Department of Children and Family Services (DCFS). The ratio and group-size rules both live in a single section — §407.190 — which makes Illinois one of the more straightforward states to reference, even though the mixed-age rules underneath it have some genuinely distinctive flexibility built in.

Current Ratios by Age Group (§407.190(a))

Illinois state child care facility staff to child ratios

Illinois uses the same ratio indoors and outdoors.

Maximum Group Size (§407.190(a))

Illinois does cap group size at every age band (up to 30). One notable exception, spelled out directly in §407.190(b): an early childhood teacher paired with an early childhood assistant may supervise a group of up to 30 children, provided every child in that group is at least five years old — effectively a higher-capacity option specific to kindergarten-and-up classrooms staffed with a teacher/assistant pair.

Mixed-Age Groups (§407.190(c) and (d))

Illinois uses a clean youngest-child governs rule: whenever children of different ages are combined in an allowed way, both the ratio and the group-size cap for the entire room follow the youngest child present (§407.190(c)).

Combinations are only permitted in specific, enumerated ways under §407.190(d) — it isn't a free-for-all:

Infants, toddlers, and two-year-olds may be combined.
Two-year-olds through five-year-olds may be mixed in any combination.
Four-year-olds through six-year-olds may be mixed.
Children of any age may be mixed during the first hour and last hour of programs operating 10 or more hours per day — a provision similar in spirit to Texas's opening/closing adjustment, though Illinois frames it as a full age-mixing allowance rather than a ratio relaxation.

There's also a supervision flexibility clause: once all children in a group are two years or older, a qualified early childhood assistant (18+) may independently supervise the classroom without an early childhood teacher present, provided specific training requirements are met (§407.190(f)).

Floor Space

Indoor (§407.370): 35 square feet of activity space per child for children 2 years and older, excluding administrative space, storage, bathrooms, kitchens, and large-muscle-activity rooms like gymnasiums. Infants and toddlers are calculated differently, based on how play and sleep space is arranged: infants require 25 square feet of play space plus 30 square feet of sleeping space per child regardless of whether play and sleep happen in the same or separate rooms; toddlers require 55 square feet per child if play and sleep share one room, or 35 square feet of play space plus 30 square feet of sleeping space if the two are in separate rooms.
Outdoor (§407.390): 75 square feet of safe outdoor area per child, based on the number of children using the space at any one time. Children under 24 months may not share a common outdoor play area at the same time as children ages 3 and up.

Illinois also has a specific urban waiver provision worth knowing about: DCFS may waive the on-site outdoor play area requirement entirely if a facility is located where suitable outdoor space genuinely isn't available, provided the center instead offers an indoor gross-motor activity room of at least 75 square feet per child for at least 25% of licensed capacity, and parents are notified in writing at enrollment. A center may also use a nearby park, schoolyard, or other off-site space in place of its own play area, subject to Department approval on a case-by-case basis — a structural parallel to how NYC and New York State both handle outdoor space in tightly built areas, even though Illinois arrives at it through a formal waiver process rather than a blanket statewide allowance.

A Bit of History: DCFS, and a Regulatory Shift Already in Motion

Illinois's child care licensing framework traces back to the Child Care Act of 1969 (225 ILCS 10), which remains the statutory authority behind Part 407 today — the ratio table itself has been revised multiple times since (most recently effective October 30, 2023), but the underlying legal authority is over 55 years old.

Worth flagging for anyone tracking this space closely: Illinois is in the middle of a genuine structural change. Legislation moving through the 2026 legislative session amends both the Early Childhood Act and the Child Care Act of 1969 to shift fingerprint-based background check authority for child care providers from DCFS to a newly created agency — the Illinois Department of Early Childhood (IDEC) — effective July 1, 2027 (DCFS retains that authority in the interim, pending federal approval for IDEC to take it over). This is part of a broader trend of states carving early childhood functions out of general family-and-protective-services agencies into dedicated early learning departments. It doesn't change the §407.190 ratio numbers themselves, but it's a signal that the regulator behind Illinois child care licensing may look different within the next couple of years — worth a bookmark if you're tracking Illinois long-term.

Illinois is also unusual in explicitly noting that Chicago does not set its own separate ratios. The city layers on its own municipal licensing and inspection requirements, but the numeric ratio, group-size, and space standards are the statewide Part 407 figures — Chicago is an administrative overlay, not a separate regulatory jurisdiction the way New York City is relative to New York State.

Why This Is Harder to Track Than It Looks

Illinois's headline ratio table is short, but real compliance depends on knowing which of the four enumerated mixed-age combinations actually applies to a given room, whether the teacher-plus-assistant 30-child exception is available, and whether a center's outdoor space qualifies for the urban waiver or needs to meet the standard 75-square-foot figure outright. Layer in a regulator transition already scheduled for 2027, and it's easy to see how a center could be confidently citing the right numbers today while missing a structural change that's coming down the pipeline. That's exactly the kind of moving target [App Name] is built to track automatically, rather than requiring a Part 407 re-read every time a room's composition changes.

References & Sources

Disclaimer: This guide reflects Illinois 89 Ill. Admin. Code Part 407 regulations as researched and is intended as a general reference, not legal advice. Always verify current requirements against the official Illinois Administrative Code or your licensing representative for your specific program.

Illinois Child Care Staff-to-Child Ratios: The Complete Section 407.190 Guide