Parque Estadual do Espinilho, State park in Rio Grande do Sul, Brazil.

Parque Estadual do Espinilho covers 1,617.14 hectares at the confluence of the Quaraí and Quaraí Mirim rivers, in Barra do Quaraí, in the Campo Osório area. It protects a savanna parkland of espinilho trees, algarrobo (Prosopis nigra) and inhanduvay (Prosopis affinis), with some quebracho blanco, on hydromorphic carbonate soils. The espinilho is a thorny tree up to three metres tall whose one-centimetre capsule holds the seeds.

The park was created in 1975 by State Decree No. 23,798, initially covering 276 hectares. State Decree No. 41,440 of 28 February 2002 expanded it to 1,617.14 hectares. It lies at the start of the river confluence in the area once called Campo Osório, where Admiral Saldanha da Gama was killed during the 1893 revolution.

The park lies in the area once called Campo Osório, where Admiral Saldanha da Gama was killed in 1893 during the Federalist Revolution. The name Espinilho comes from the thorny tree, up to three metres tall, that gives the park its name and dominates its savanna vegetation.

The site is currently closed to public visitors but is used by researchers for ecological and environmental studies. Anyone interested in the work being done there should contact the operators in advance.

The area is home to distinctive tree species like Prosopis nigra and Prosopis affinis, which are adapted to dry conditions. Additionally, it harbors impressively large colonies of leaf-cutter ants that shape the ecosystem.