Seattle became King County Seat on January 11, 1853. King County was named for William R. King (1852–2005) and renamed in honor of Reverend Doctor Martin Luther King, Jr. on July 24, 2005.
On February 24, 1986, the King County Council approved a motion to rename the county to honor civil rights leader Martin Luther King Jr. (no relation to William R. King), preserving the name “King County” while changing its namesake.
Because only the state can charter counties, the change was not made official until April 19, 2005, when Governor Christine Gregoire signed into law Senate Bill 5332, which provided that “King county is renamed in honor of the Reverend Doctor Martin Luther King, Jr.” effective July 24, 2005.
October 14, 1964, Dr. Martin Luther King, Jr. won the Nobel Peace Prize for combating racial inequality through nonviolent resistance.