Bluegrass and stone wall of local limestone in central Kentucky.

Kentucky River in the Bluegrass region.

The Bluegrass region is a region of the United States. The Bluegrass region, centered around Lexington, is generally considered to include central and northern Kentucky with a small area extending into southern Ohio. The region gets its name from Bluegrass, the common name for grass of the genus Poa, which is a favored lawn and pasture grass in the eastern United States from Tennessee northward.

The Bluegrass region is characterized by underlying fossiliferous limestone, dolostone, and shale of the Ordovician geological age. Hills are generally rolling, and the soil is highly fertile for growing pasture. Because of this, the Bluegrass is well known for its horse farms. However, the area is becoming more developed, particularly around Lexington, and farms are disappearing to development.

The Kentucky Bluegrass is bounded on the east by the Cumberland Plateau, with the Pottsville Escarpment forming the boundary. On the south and west, it borders the Pennyroyal Plateau, (also called the Pennyrile), with Muldraugh Hill, another escarpment, forming the boundary. Much of the region is drained by the Kentucky River and its tributaries. The river cuts a deep canyon through the region, preserving meanders that indicate that the river was once a mature low valley that was suddenly uplifted. Particularly near the Kentucky River, the region exhibits karst topography, with sinkholes, caves, and disappearing streams which drain underground to the river.

The area gave its name to Bluegrass music, which is popular throughout Appalachia and the South.