Lake Hartwell is a man-made reservoir bordering Georgia and South Carolina on the Savannah, Tugaloo, and Seneca Rivers. Lake Hartwell is one of the southeast's largest and most popular recreation lakes. The lake is created by Hartwell Dam located on the Savannah River seven miles (11 km) below the point at which the Tugaloo and Seneca Rivers join to form the Savannah. Extending 49 miles (79 km) up the Tugaloo and 45 miles (72 km) up the Seneca at normal pool elevation, the lake comprises nearly 56,000 acres (230 km²) of water with a shoreline of 962 miles (1,548 km). The entire Hartwell “Project” contains 76,450 acres (309 km²) of land and water. I-85 bisects Hartwell Lake and makes the area easily accessible to visitors.

Hartwell is a village in central Buckinghamshire, England. It is to the south of Aylesbury, by the village of Stone.

The village name is Anglo Saxon in origin, and means "spring frequented by deer". In the Domesday Book of 1086 it was recorded as Herdeuuelle and Herdewelle.

The ruined Hartwell church was designed by the architect Henry Keene and completed in 1756. It is one of the most important early Gothic revival churches in England and is Grade II* listed. It has an octagonal centre with twin towers. In the north and south bays are rose windows, other windows are represented as ogee arches. In the clerestory are quatrefoil windows. Inside, the church once had a plaster fan vault but this has now fallen in, and the church's windows are boarded. Today the building appears more as a garden folly, than a former place of worship.

Attached to the estate is the former hamlet of Lower Hartwell.

Hartwell House in the village is a grade I listed building in a 90-acre park, part of the Hartwell Estate owned by the Ernest Cook Trust. The house was once the residence of the exiled future king of France Louis XVIII. Since 2008 it has been leased to the The National Trust and is run as a hotel by an independent company, Historic House Hotels Ltd.