TOSCA, TEXAS. Tosca was in northwestern Blanco County on the Blanco-Gillespie county line twelve miles northwest of Johnson City. A post office was established there in 1915 but closed in 1931. The post office was in the limestone ranchhouse built in the 1880s by August Grote, who emigrated from Germany in the 1860s, and was operated by his son Alex Grote and Alex's wife, Julia. Their son Ernest Grote later restored the house and was still living there in 1999.