Newcastle is a city in Young County, Texas, United States. Following the beginning of coal mining in 1908, the town was established and named for the English coal town, Newcastle upon Tyne. Coal mining had ended by 1942. The population was 575 at the 2000 census.
Newcastle is located at 33°11′33″N 98°44′17″W / 33.1925°N 98.73806°W / 33.1925; -98.73806 (33.192383, -98.737969).
According to the United States Census Bureau, the city has a total area of 1.8 square miles (4.7 km²), all of it land.