The East Texas Oil Field is a large oil and gas field

Oil reservoir

A petroleum reservoir, or oil and gas reservoir, is a subsurface pool of hydrocarbons contained in porous or fractured rock formations. The naturally occurring hydrocarbons, such as crude oil or natural gas, are trapped by overlying rock formations with lower permeability...

 in east Texas

Texas

Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

. Covering 140000 acres (566.6 km²) and parts of five counties, and having 30,340 historic and active oil wells, it is the largest oil field in the United States outside of Alaska, both in extent and in total volume of oil recovered since its discovery in 1930. It is a component of the Mid-Continent Oil Province

Mid-continent Oil Field

The Mid-continent oil field is a broad area containing hundreds of oil fields in Arkansas, Kansas, Louisiana, New Mexico, Oklahoma and Texas. The area, which consists of various geological strata and diverse trap types, was discovered and exploited during the first half of the 20th century...

, the huge region of petroleum deposits extending from Kansas

Kansas

Kansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south...

 to New Mexico

New Mexico

New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

 to the Gulf of Mexico

Gulf of Mexico

The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...

.

The field includes parts of Gregg

Gregg County, Texas

There were 42,687 households out of which 33.50% had children under the age of 18 living with them, 52.00% were married couples living together, 13.50% had a female householder with no husband present, and 30.50% were non-families. 26.10% of all households were made up of individuals and 10.50% had...

, western Rusk

Rusk County, Texas

As of the census of 2000, there were 47,372 people, 17,364 households, and 12,727 families residing in the county. The population density was 51 people per square mile . There were 19,867 housing units at an average density of 22 per square mile...

, southern Upshur

Upshur County, Texas

As of the census of 2000, there were 35,291 people, 13,290 households, and 10,033 families residing in the county. The population density was 60 people per square mile . There were 14,930 housing units at an average density of 25 per square mile...

, southeastern Smith

Smith County, Texas

As of the census of 2000, there were 174,706 people, 65,692 households, and 46,904 families residing in the county. The population density was 188 people per square mile . There were 71,701 housing units at an average density of 77 per square mile...

, and northeastern Cherokee

Cherokee County, Texas

As of the census of 2000, there were 46,659 people, 16,651 households, and 12,105 families residing in the county. The population density was 44 people per square mile . There were 19,173 housing units at an average density of 18 per square mile...

 counties in the northeastern part of the state.