Thomas Holbrook (born May 23, 1949) is an Illinois politician who serves as the St. Clair County Clerk. He was appointed to replace Bob Delaney.[1][2] Prior to this he served as Chairman of the Illinois Pollution Control Board from 2011 to 2013[3] and a Democratic member of the Illinois House of Representatives representing the 113th District for eight terms from 1995 until 2011.