Hobart is an unincorporated community and census-designated place in King County, Washington, United States. The population was 6,221 at the 2010 census. Based on per capita income, one of the more reliable measures of affluence, Hobart ranks 31st of 522 areas in the state of Washington to be ranked. The Hobart area was first settled by loggers in 1879, and originally known as "Vine Maple Valley". The name was changed when deemed too long by the Post Office. The Hobart Post Office was first opened May 9, 1903 with William Sidebotham as first postmaster A coal mine also operated in the area as late as 1947.