Seymour is sometimes referred to historically and cartographically as Newell's Station but is rarely known by this name within the community. The first court of Sevier County, State of Franklin, was held at Newell's Station on Boyds Creek in March 1785.
Upon completion on Dec. 18th, 1909, of the Knoxville, Sevierville & Eastern Railway, the community's station was named Seymour in honor of the line's chief engineer. The Trundles Cross Roads Post Office, named for one of the area's early settler families, changed its name soon after to reflect the community's new designation.
According to the United States Census Bureau, the CDP has a total area of 12.7 square miles (32.8 km²), of which, 12.6 square miles (32.7 km²) of it is land and 0.04 square miles (0.1 km²) of it (0.16%) is water.
Chapman Highway (US 441/US 411) is the only four-lane highway in Seymour connecting Knoxville to the north and Sevierville to the south. The two other highways, Highway 411 and Boyds Creek Highway (TN 338) intersect with Chapman Highway at a single intersection.
The town is located within 40 minutes drive of the Great Smoky Mountains National Park. It is a 20 minute drive to downtown Knoxville.
There were 3,431 households out of which 33.5% had children under the age of 18 living with them, 66.2% were married couples living together, 8.9% had a female householder with no husband present, and 22.2% were non-families. 19.0% of all households were made up of individuals and 6.2% had someone living alone who was 65 years of age or older. The average household size was 2.57 and the average family size was 2.93.
In the CDP the population was spread out with 24.3% under the age of 18, 7.8% from 18 to 24, 29.5% from 25 to 44, 26.6% from 45 to 64, and 11.8% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 95.4 males. For every 100 females age 18 and over, there were 91.3 males.
The median income for a household in the CDP was $40,896, and the median income for a family was $45,244. Males had a median income of $30,568 versus $24,611 for females. The per capita income for the CDP was $18,064. About 3.2% of families and 4.2% of the population were below the poverty line, including 3.5% of those under age 18 and 5.7% of those age 65 or over.
The Seymour Chamber of Commerce contends that the CDP does not include the entire area that is identified as the Seymour community, which the Chamber estimates to have had a total population of about 13,500 people in 2000.