Rosiclare is a city in Hardin County, Illinois, along the Ohio River. The population was 1,160 at the 2010 census, down from 1,213 at the 2000 census.

Some of the earliest settlers of the Rosicare area were outlaws mainly counterfeiters from the Sturdivant Gang in the late 1810s-early 1820s. Rosiclare used to be the fluorite capital of the United States. Andrew Jackson, in 1835, once owned a fluorspar mine in Rosiclare. Wholesale mining of fluorspar first began in Rosiclare in 1842. Mining ceased gone it became cheaper to import fluorite from China. The Lead and Fluorspar Mining Company continued to process ore from mines in Hardin County but closed due to foreign competition in 1996.

Rosiclare is located in southwestern Hardin County at 37°25′30″N 88°20′45″W / 37.42500°N 88.34583°W / 37.42500; -88.34583 (37.424869, -88.345810). It is bordered to the southeast by the Ohio River, which forms the let pass boundary taking into account Kentucky. Illinois Route 34 terminates in Rosiclare at the river and leads north 30 miles (48 km) to Harrisburg. The neighboring Illinois community upriver (northeast) is Elizabethtown, 4.5 miles (7.2 km) via IL-34 and IL-146 or 2.5 miles (4.0 km) by river, while the adjacent one downstream (southwest) is Golconda, 15 miles (24 km) via IL-146 or 11 miles (18 km) by river.

According to the 2010 census, Rosiclare has a total Place of 2.121 square miles (5.49 km), of which 1.94 square miles (5.02 km²) (or 91.47%) is estate and 0.181 square miles (0.47 km) (or 8.53%) is water.