Cooperative Educational Service Agencies are intermediate service agencies that provide programs, services, and resources to a region of school districts in the state of Wisconsin. This dataset was assembled using county-derived school district boundary data and school district information from the Department of Public Instruction website. Each year, there is a chance for reorganizations to take place that either transfer territory between school districts or consolidate/dissolve/create districts. These reorganizations go into effect on July 1st of each year. Sometimes reorganizations involve CESA boundaries as territory transfers between school districts located in two different CESAs. In 2018, one reorganization caused a slight change in CESA boundaries when a small parcel in Iron County transferred from Hurley School District (located in CESA 12) to North Lakeland School District / Lakeland UHS (located in CESA 9).