Nine-Mile Prairie (named for its location 5 miles (8.0 km) west and 4 miles (6.4 km) north of downtown Lincoln) is a 230-acre (0.93 km2) tract of conserved tallgrass prairie in Lancaster County, Nebraska, United States.

[1] The area was previously owned by the Department of Defense and served as part of a fenced buffer zone around a World War II era bomb storage depot.

In addition to prairie grasses, some of which including big bluestem (Andropogon gerardii) can grow as tall as six feet, the site supports a range of prairie trees, including cottonwoods and honey locust.

Invasive sumac plants and (in the absence of fire) eastern juniper trees require control to preserve the original prairie ecology.

Notable species include the federally threatened prairie white fringed orchid (Platanthera praeclara) and the rare regal fritillary butterfly (Speyeria idalia), and it is home to bluebirds and white-tailed deer; herds of bison would have also passed through the site when it was open prairie until the mid-19th century.