Question: Walker County was named after which member of the US Senate from Mississippi?

Context paragraphs:
Jasper, Alabama: Jasper is a city in Walker County, Alabama, United States.  At the 2010 census the population was 14,352, up from 14,052 in 2000.  The city is the county seat of Walker County, and once ranked among the world's leading producers of coal.  The town is also the location of the SyFy Channel's documentary show "Town of the Living Dead". The City is also home to the annual "Foothills Festival" that happens every year in "Historic Downtown Jasper Square."  They hold Live Music and food vendors all around the square.  In 2017 the dates for the "Foothills Festival" have been announced for September 15 and September 16.  http://www.foothillsjasper.com/

Bankhead Lake: Bankhead Lake is a reservoir along the Black Warrior River that begins in Walker County in the state of Alabama.  The lake forms the border between Jefferson and Tuscaloosa County, as well as the border dividing Jefferson and Walker County.  It eventually empties into Holt Lake.

Dodge, Texas: Dodge is an unincorporated community in eastern Walker County, Texas, United States, on the northern edge of the Sam Houston National Forest.  It lies along FM 405 east of the city of Huntsville, the county seat of Walker County.  Its elevation is 400 feet (122 m).  Although Dodge is unincorporated, it has a post office, with the ZIP code of 77334; the ZCTA for ZIP Code 77334 had a population of 184 at the 2000 census.

Chickamauga City School District: The Chickamauga City School District is a public school district in Walker County, Georgia, based in Chickamauga.  It serves the city of Chickamauga and the surrounding communities in Walker County.

Walker County Board of Education: Walker County Board of Education is the governing body over the public schools in Walker County, Alabama, United States.

Walker County School District: The Walker County School District is a public school district in Walker County, Georgia, United States, based in LaFayette.  It serves the communities of Chattanooga Valley, Chickamauga, Fairview, Flintstone, Fort Oglethorpe, LaFayette, Lakeview, Lookout Mountain, and Rossville.

Walker County, Texas: Walker County is a county located in the east central section of the U.S. state of Texas.  As of the 2010 census, its population was 67,861.  Its county seat is Huntsville.  Initially, Walker County was named for Robert J. Walker, a legislator from Mississippi who introduced into the United States Congress the resolution to annex Texas.  Walker later supported the Union during the Civil War and earned some enmity.  In order to keep the county's name, the state renamed it for Samuel H. Walker, a Texas Ranger and soldier in the American Army.

Walker County Jane Doe: Walker County Jane Doe is an unidentified murder victim discovered on November 1, 1980, in Huntsville, Walker County, Texas.  After the investigation of her murder and identity went cold, she was buried in a donated casket in Oakwood Cemetery in the same town where she was found.  To this day, she has yet to be identified, even though her face has been reconstructed several times.

Robert J. Walker: Robert John Walker (July 19, 1801November 11, 1869) was an American lawyer, economist and politician.  An active member of the Democratic Party, he served as a member of the U.S. Senate from Mississippi from 1835 until 1845, as Secretary of the Treasury from 1845 to 1849 during the administration of President James K. Polk, and briefly as Territorial Governor of Kansas in 1857.

Walker County Airport: Walker County Airport (ICAO: KJFX) , also known as Bevill Field, is a public airport located five miles (8 km) northwest of the central business district of Jasper, a city in Walker County, Alabama, United States.  It is owned by the Walker County Commission.

Supporting paragraphs: Walker County, Texas Robert J. Walker
Answer: Robert J. Walker