Covington is a city in, and the parish seat of, St. Tammany Parish, Louisiana, United States. The population was 11,564 at the 2020 Uniā¦Covington is a city in, and the parish seat of, St. Tammany Parish, Louisiana, United States. The population was 11,564 at the 2020 United States census. It is located at a fork of the Bogue Falaya and the Tchefuncte River. Covington is part of the Slidell-Mandeville-Covington, LA metropolitan statistical area. Covington has played a large role in movie making over the past 20 years, featuring in over 30 films.