Mother Neff State Park is a 259-acre (105 ha) state park located on the Leon River west of Moody, Texas in Coryell County. The park is part of Mother Neff State Park and F.A.S. 21-B(1) Historic District, which was added to the National Register of Historic Places on October 2, 1992.

The park's initial 6 acres (2.4 ha) were donated by Mrs. Isabella Eleanor Neff, mother of Governor Pat Morris Neff in 1916. Upon her death in 1921, Governor Neff created the Mother Neff Memorial Park, making it the first state park in Texas. The additional land was deeded to the state in 1934 by private owners; Governor Neff deeded 250 acres (100 ha) and Mr Frank Smith deeded 3 acres (1.2 ha). The park was opened to the public in 1937.

Company 817 of the Civilian Conservation Corps built the park from 1934 to 1938. The company used local materials such as limestone and local hardwoods (oak, elm, juniper, and cottonwood) to build the entrance portals, concession club house, caretaker’s building, pump and drainage systems, fences, and picnic areas. They also built roads, trails and terraced the flood plain.

Most of Mother Neff Park sits in the flood plain of the Leon River and flooding shut the park down in 1992 and 2007. Flooding in 2015 closed the lower half of the park, and the section is not reopened as of 2024.

Texas F.A.S. [federally assisted secondary road] 21-B(1) (County Road 314 locally known as Old River Road or Oglesby Neff Park Road) is a 6-mile (9.7 km) length of road built in 1939. The Texas State Highway Department constructed the road using allocated federal funds. The road follows the Leon River for much of its length from the west entrance of the park to Farm to Market Road 107.

• List of Texas state parks
• National Register of Historic Places listings in Coryell County, Texas

Media related to Mother Neff State Park at Wikimedia Commons

• Texas Parks and Wildlife Department: Mother Neff State Park
• U.S. Geological Survey Geographic Names Information System: Mother Neff State Park