Innerthal is a municipality in March District in the Canton of Schwyz in Switzerland .

Innerthal is first mentioned in 1259 as Wegental. Until 1888 it was known as Hinterwäggithal.

As of 2006 Innerthal has an area of 50.2 km2 (19.4 sq mi). Of this area, 34.9% is used for agricultural purposes, while 34.1% is forested. Of the rest of the land, 0.4% is settled (buildings or roads) and the remainder (30.6%) is non-productive (rivers, glaciers or mountains).