The community is associated with Erin Brockovich who, as a legal clerk to the lawyer Edward L. Masry, investigated Pacific Gas & Electric for their contribution to unclean water in the town. The water contained hexavalent chromium, which was accepted as being a carcinogen, though some studies find no relationship between chromate and cancer. Her successful fight against PG&E became well known in the public's mind, as did Hinkley, when the film of her story was released in 2000 (Erin Brockovich).
The United States does not define a census-designated place called Hinkley, but it does define a Zip Code Tabulation Area (ZCTA), 92347. Because Hinkley is contained within this ZCTA, it is possible to obtain Census data from the United States 2000 Census for the area even though data for "Hinkley" is unavailable. As of the census of 2000², the ZCTA of 92347 had a 2000 population of 1,915. Of note is the fact that there were 485 people (26.7 percent of the population) five years in age or older categorized as having a disability, a higher than average figure when compared to the national average of about 19.3 percent.
Between the 1960s and 1980s, there was Hawes Radio Tower, a guyed mast used for military communication in the LF-range.