Deerfield is a village in Lake County, Illinois, United States, approximately 25 miles north of Chicago with a small portion extending into Cook County, Illinois. The population was 18,225 at the 2010 census, a decline of 175 from 2000.Deerfield is home to the headquarters of Walgreens, Baxter Healthcare, Business Technology Partners, APAC Customer Services, Fortune Brands Home & Security , Takeda Pharmaceutical Company's US HQ, Consumers Digest, and Mondelēz International. Deerfield High School is one of the top high schools in the state, ranking #5 in 2012.Deerfield is represented by the 10th Congressional District of Illinois, 29th District of the Illinois Senate and the 58th District of the Illinois House of Representatives.