Human services cover a broad range of programs, services, and facilities provided to the public that are designed to enhance the quality of life and well-being of people and communities. In most cases, human services are provided by agencies at the community level and include programs and services such as affordable housing, child care, mental health and substance use treatment, and job training, as well as those targeting specific populations such as immigrants, seniors, or people experiencing homelessness.This paper outlines an approach to estimating the size of the human service workforce in Illinois. Quantifying the size of Illinois' human service workforce fills a knowledge gap; with such diversity among human service organizations, a total figure for the entire sector has not before been estimated. An estimate of workers employed in human service organizations gives a sense of how much of the workforce is dependent on human service jobs. Additionally, it gives context and illustrates the relative size of this portion of the workforce to examine cross state comparisons in terms of the number of human service workers to residents in each state