1. Start with the geography you actually serve
South Barrington is a municipality in Cook County, Illinois. The 2020–2024 ACS five-year population estimate is 5,021, with a margin of error of 96. It does, however, make geographic discipline important: a South Barrington service area should not automatically be treated as all of Cook County, the Chicago metropolitan area, or Illinois.
Recommended approach
During evaluation, define the geographic labels your firm uses for South Barrington, Cook County and any broader service area. Ask how those labels will be represented in landing-page and intake records, then review whether the resulting data supports a decision about coverage. Keep municipality, county, metropolitan area, household and individual descriptions separate in both reporting and client conversations.
