Polk County, named after then President James K. Polk, was one twenty-three counties formed by the first State Legislature of Texas in 1846. Livingston, formerly Springfield, was selected by a vote as the county seat in 1846, and the first commissioners' court met there in September of that year.

In the late 1700's, the present Polk County became the home of the Alabama and Coushatta Indian tribes. Through the interest and concern of Sam Houston, then General of the Republic of Texas, the Alabama Indians were given a permanent home in the eastern portion of the county. Subsequently, members of the Coushatta tribe also settled on the reservation. Today, the federally recognized "Alabama-Coushatta Tribe of Texas" resides on the 4,600 acre Indian Reservation, the largest and oldest in the State.

Plantations dominated the county economically and politically before the Civil War. The population of the county in 1860 was 8,300. The county produced 9,307 bales of cotton in 1859. The coming of the railroads to the Polk County area in the 1800's drastically changed the local economy. The railroads were instrumental in the transition of Polk County from a farming to a timber economy. Logs cut and milled by local residents were transported by rail to help build a growing nation.

In the twentieth century the value of the lumber industry increased remarkably. The greatest increase came after World War II, but the lumber boom helped ease the impact of the Great Depression on the county. Jobs in the timber and related service industries doubled between 1930 and 1940.

The county also yields some oil and gas: 703,007 barrels of crude oil and 1.8 billion cubic feet of gas-well gas were produced in 1982; crude production in 1990 was 1,256,622 barrels. In 1990 Polk County was the leading Texas county in lumber products and Christmas trees.

Polk County developed its utilities during the period of increasing population between 1880 and 1940. The Livingston Telephone Company was organized on August 3, 1903, with forty telephones in service.

The Livingston Power Plant began providing electricity at night in 1905 from a small wood-fired steam engine. Several local businessmen purchased the plant in 1907 and initiated daylight service in 1909.

Education in the county began in 1843, when the Masons in Swartwout allowed their lodge to be used for a schoolhouse; they reopened the school when they moved to Livingston in 1849.

The parent publication of the Polk County Enterprise was the East Texas Pinery, originally printed in the small community of Moscow in 1881. The Enterprise is now published in Livingston, where the first newspaper in the county, the Rising Sun, began in 1858. In 1980 the majority of the fifty-nine churches in the county were Southern Baptist, Baptist Missionary, and United Methodist. The county was voted dry in 1908 and remained as such until a local option election to allow sales of beer and wine was passed county wide in 2006.

Construction of the 93,000 acre Lake Livingston was completed in 1968 and is located in the west and southwest portion of the county. It continues to play a great role in the local economy. Water stored in the lake is used to supply industrial, municipal and agricultural needs in the lower Trinity River Basin and the greater Houston area, as well as municipalities within the county.

Over 50 historical markers can be visited throughout the county recognizing the past that is Polk County.