Ada is a city in and the county seat of Pontotoc County, Oklahoma, United States. The population was 16,008 at the 2000 census. Ada is an Oklahoma Main Street City, an Oklahoma Certified City, a Tree City USA member, and a National Weather Service StormReady Community.
East Central University (ECU) is a four year public university in Ada, Oklahoma, located in the south central region of the state. The university also has courses available in McAlester, Shawnee, Ardmore, and Durant.