Joseph Jefferson Mansfield was born on February 9, 1861 at the town of Wayne in what was then Virginia, but which shortly afterward became West Virginia. He is pictured above in his mid-twenties, c. 1885, in his late forties, c. 1910, and in his late sixties c. 1930. He had a long and distinguished political career, serving as city attorney of Eagle Lake in 1888, mayor of Eagle Lake from 1889-1892, county attorney of Colorado County from 1892-1896, county judge of Colorado County from 1896-1916, and United States congressman from March 4, 1917 until his death on July 21, 1947. He was referred to as Joe until he was elected county judge. Ever afterward, he was universally called Judge Mansfield.

Annie Scott Bruce, wife of Joseph Jefferson Mansfield, was born October 22, 1867 and died January 4, 1937.   Jaquelin Smith Bruce, father of Annie Scott Bruce, was a physician in Eagle Lake, Texas. He was born October 10, 1836 and died March 22, 1929.

Joseph Jefferson Mansfield's parents were Joseph Jefferson Mansfield and Amanda (Smith) Mansfield. The senior Joseph Jefferson Mansfield was an officer in the Confederate States Army, and was killed July 22, 1861. After his death, his widow changed the name of their infant son from what it had been, Beauregard. Later, she remarried, first to a physician named H. Walker, then to a man named Osburn. She was born in 1829 and died on February 17, 1927.

Joseph Jefferson Mansfield came to Texas in 1881. In a reminiscence he dictated in 1943, he recalled that he left home on April 7, met his step-brother Millard F. Walker at Cincinnati, Ohio, then proceeding by train to Houston and, finally, Alleyton, Texas. The trip took seven days. However, on February 17, 1881, nearly two months before he claimed to have left his home, his name appeared in the Columbus, Texas newspaper, the Colorado Citizen, as an employee of the Val Verde Nursery in Alleyton. He worked at the nursery for a few years, becoming active in the community. He began his legal career in 1886, when he was admitted to the bar.

Jaquelin Smith Bruce was one of only two men who answered to his own name when the mustering-in of a company that was raised for the Confederate States Army in Columbus was reenacted at the city's centennial celebration in 1923. The same year, he wrote a series of reminiscences that were published in his hometown newspaper, the Eagle Lake Headlight.

Annie Scott Bruce was the daughter of Jaquelin Smith Bruce and Minna (Rivers) Bruce. Her mother was the daughter of a prominent early-Texas attorney, Robert Jones Rivers. She married Joseph Jefferson Mansfield on January 18, 1888. For some years, she taught private music lessons in Columbus. She was admitted to a Houston hospital on December 9, 1936, about one month before she died there.

Jaquelin Smith Bruce married Minna Rivers in 1866. The couple had one child before she died in 1869. In 1872, Bruce married his first wife's sister, Susie.

The Mansfields had four children. Their son Bruce Jefferson Mansfield was born about 1890 and died May 11, 1966. He is buried in Washington, D. C. Their three daughters were Susie, Margaret Byrd (born February 1, 1893), and Jaquelin Amanda (born May 21, 1900). Susie died as an infant. Margaret married Richard Porter Dorsey on June 24, 1933 and lived with him in Baltimore, Maryland. She died December 25, 1970. Jaquelin married George Frank "Doc" Schmidt on July 20, 1928, and spent most of her life in Guadalupe County, Texas. She died there on January 23, 1997.

Joseph Jefferson Mansfield was very active in the Masons. In 1912-1913, he was grand master of the Texas Grand Lodge of Masons.

Bruce Jefferson Mansfield served as an officer in the United States Army during World War I.

In August 1921, Joseph Jefferson Mansfield became ill. He was confined to his bed for the next several months. When he returned to his duties in the United States House of Representatives, on April 9, 1922, he was in a wheelchair. He never walked again.

Joseph Jefferson Mansfield was a major player in the effort to dam the Colorado River in Texas. He became chairman of the House's Rivers and Harbors Committee in 1931. He secured key federal funding for the project, and worked closely with the people who created and managed the Lower Colorado River Authority. In 1941, the Colorado River dam that was originally called Marshall Ford Dam, was named Mansfield Dam in his honor.

Joseph Jefferson Mansfield, Annie Scott Bruce Mansfield, Susie Mansfield, and Jaquelin Smith Bruce, are all buried in the Masonic Cemetery in Eagle Lake, Texas.

On April 23, 1949, the community of Port Mansfield in northeastern Willacy County, Texas, was dedicated and named in honor of Judge Mansfield.