Thornfield is an unincorporated community in Ozark County, Missouri. It is northwest of Gainesville. It is located on Route 95 at the Little North Fork of the White River on the edge of the Mark Twain National Forest between Wasola to the northeast and Longrun to the southwest. Hammond, the site of the historic Hammond Mill, lies on the Little North Fork southeast of Thornfield.
Thornfield is served by a post office with ZIP code 65762.
Thornfield R-1 Elementary School lies about one mile east of the town on Route 95.