The suburb is planned, but building has not begun. The postcode is 2913. It is next to the suburbs of Kinlyside, Taylor, lying to the west of Ngunnawal, Australian Capital Territory. It is bounded by Horse Park Drive and Clarrie Hermes drive.
In 2007, 2000 blocks were marked for release, indicating that Casey will be the next Gungahlin suburb to be developed, presumably after Franklin.
The landscape slopes to the south east, with a line of hills forming a ridge on the north west side making a backdrop. The low point is 622 meters at the roundabout joining Gungahlin Drive, Horse Park Drive and Clarrie Hermes drive. The highest point is 726 meters in the north west corner.
The whole suburb is underlaid by rocks from the Silurian period. Along the hill tops the rock is from the Hawkins Volcanics, with mostly dacite in the south, and andesite in the north. The north east of the suburb has dacite from the Canberra Formation. The south east has a green grey porphyry with a dacite like composition, and visible white feldspar crystals.