Gabis Arboretum at Purdue Northwest is a 360-acre nature preserve and botanical garden near Valparaiso, Indiana, encompassing prairie, woodland, wetland, savanna, and display gardens. Especially noted for the largest collection of oak trees in Indiana, it also features collections of native plants, viburnums, conifers, Japanese maples, roses, and flowering trees. The project began in 1990 when Damien Gabis and local residents bought 72 acres to protect prairie land, later expanding to 360 acres and 20,000 planted trees. Founded as Taltree Arboretum in 1998, it added a garden railway in 2011 and came under Purdue University Northwest on January 31, 2018, while continuing as both a protected landscape and public garden.