Garland is primarily located in Dallas County, with small portions extending into Collin and Rockwall counties. It is situated within the Texas Blackland Prairies, an ecological region historically characterized by rich, dark, clay soils and tallgrass plains, though the area is now highly urbanized.
The city's landscape is defined by its waterways and green spaces. The most prominent geographic feature is Lake Ray Hubbard, a sprawling reservoir on the eastern edge of the city that serves as both a water supply and a major recreational hub. A network of creeks—most notably Duck Creek, Spring Creek, and Rowlett Creek—meanders through the city, flanked by belts of mature trees, greenbelts, and parks that provide natural buffers within the dense suburban grid.