Odessa is a city in the U.S. state of Texas and the seat of Ector County with portions extending into Midland County. Odessa's population wa…Odessa is a city in the U.S. state of Texas and the seat of Ector County with portions extending into Midland County. Odessa's population was 114,428 at the 2020 census, making it the 34th-largest city in Texas; it is the principal city of the Odessa metropolitan statistical area, which includes all of Ector County. The metropolitan area is also a component of the larger Midland–Odessa combined statistical area, which had a 2020 census population of 359,001.