Mililani sits near the center of O'ahu, a planned community that grew from former sugarcane plantation fields into one of the island's most well-organized suburban cities. Developed by Castle & Cooke beginning in the late 1950s, it was designed from the ground up to meet Honolulu County's demand for housing, and that intentional layout still shapes daily life today. Honolulu is roughly 15 miles away via H-1, and Naval Station Pearl Harbor is within a half-hour drive, anchoring Mililani as a steady hub for both civilian and military communities. Leeward Community College and the University of Hawaii West O'ahu are also nearby, adding an educational presence to the area.
Mililani is divided into two distinct sections: Mililani Town and Mililani Mauka, each with its own character while sharing the same well-planned sensibility. The surrounding landscape is largely open and undeveloped, giving the city a surprisingly spacious feel despite its density.