Delta is a city in Millard County, Utah, United States. The population was 3,209 at the 2000 census. According to the United States Census Bureau, the city has a total area of 3.2 Square miles (8.2 Square kilometer), all of it land. The Sevier River flows near Delta. The Sevier River is generally used by irrigation before it reaches its eventual end, the dry Sevier Lake.