Illinois Number of Private Business Establishments in the NAICS 561611 Investigation services Industry

Updated on April 2, 2026.

According to data from the US Bureau of Labor Statistics, in 2025 Q3, the number of Private business establishments in the NAICS 561611 Investigation services Industry in Illinois was 194.

The chart and table below shows the number of business establishments for each quarter.

You can see similar information for other industries.

You can also see similar information for other states, and for the United States.

Related Topics: Illinois BLS Topic List.

Data Source: US Bureau of Labor Statistics (QCEW).

Illinois Number of Private Business Establishments in the NAICS 561611 Investigation services Industry

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Year Quarter	Number of Business Establishments
2023 Q1	187
2023 Q2	192
2023 Q3	196
2023 Q4	199
2024 Q1	189
2024 Q2	190
2024 Q3	191
2024 Q4	192
2025 Q1	188
2025 Q2	191
2025 Q3	194