For 15 points, name this arid region of western Nebraska
The endangered blowout penstemon is a plant endemic to this region. A 1904 act sponsored by congressman Moses Kinkaid expanded the terms of the Homestead Act to allow for free land grants in this region, whose early history was dominated by large cattle ranches. Counties in this region include those named for Civil War generals Phil Sheridan, Joe Hooker, and John Logan. The Nature Conservancy's Niobrara Valley Preserve protects part of this region. The connection between this region's near-surface groundwater and the (*) Oglalla Aquifer was cited by opponents of the Keystone XL pipeline, which would have been built across this region. For 15 points, name this arid region of western Nebraska
The endangered blowout penstemon is a plant endemic to this region.
Nebraska Sandhills