Hobart is an unincorporated community and census-designated place (CDP) 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 declare of Washington to be ranked. The Hobart Place was first fixed by loggers in 1879, and originally known as “Vine Maple Valley”. The declare was changed when deemed too long by the Post Office. The Hobart Post Office was first opened May 9, 1903 next William Sidebotham as first postmaster A coal mine as well as operated in the Place as late as 1947.

Hobart is located in central King County at 47°24′56″N 122°0′21″W / 47.41556°N 122.00583°W / 47.41556; -122.00583 (47.415568, -122.005950). It is bordered to the north by Mirrormont, to the northwest by East Renton Highlands, to the southwest by Maple Valley, and to the south by Ravensdale. 2,600-foot (790 m) Taylor Mountain rises to the northeast.

Washington State Route 18 passes through Hobart, leading northeast 9 miles (14 km) to Interstate 90 close Snoqualmie and southwest 15 miles (24 km) to Auburn. Seattle is 24 miles (39 km) to the northwest.

According to the United States Census Bureau, the Hobart CDP has a total Place of 18.9 square miles (48.9 km²), of which 18.8 square miles (48.6 km²) are estate and 0.1 square miles (0.3 km²), or 0.60%, are water. The Cedar River runs along the southern and western edges of the community.