Rosanky is an unincorporated community located on Farm to Market Road 535 in southern Bastrop County, Texas, United States. Although it is unincorporated, Rosanky has a post office, with the ZIP code of 78953. The town is named for Ed Rosanky, who immigrated from Prussia and settled in the area in 1854.
The climate in this area is characterized by hot, humid summers and generally mild to cool winters. According to the Köppen Climate Classification system, Rosanky has a humid subtropical climate, abbreviated "Cfa" on climate maps.