Combine is a city in Dallas and Kaufman counties in the U.S. state of Texas. The population was 2,245 in 2020. According to the United St…Combine is a city in Dallas and Kaufman counties in the U.S. state of Texas. The population was 2,245 in 2020. According to the United States Census Bureau, the city has a total area of 7.0 square miles, of which 6.7 square miles is land and 0.31 square miles, or 4.16%, is water.