McDonald's opened its first drive-thru in 1975. The restaurant was in Sierra Vista, Arizona, near Fort Huachuca, a U.S. Army installation.
The location had a practical reason for introducing the service. Military personnel stationed at Fort Huachuca were not permitted to leave their vehicles while wearing fatigues off-post, so a drive-thru allowed them to buy McDonald's food without getting out of their cars. This made the feature useful before it became a defining part of fast-food culture.
The first McDonald's drive-thru was not the same thing as a drive-in restaurant. At a drive-in, customers typically parked and were served at their vehicles; at a drive-thru, they order and collect food through a service window. McDonald's later refined the format with dedicated lanes, speaker systems, menu boards, and faster kitchen workflows. By the late twentieth century, drive-thru service had become central to the chain's operating model.