Bonham, county seat and commercial center of Fannin County, is on U.S. Highway 82 and State highways 78 and 121 on the northern edge of the Blackland Prairie twelve miles south of the Red River. Settlement began with the arrival in 1836 of Bailey Inglish from Butler County, Kentucky. In 1837 he built Fort Inglish, a blockhouse and stockade, on 1,250 acres of land located on Bois d'Arc Creek near timber and water supplies. John P. Simpson came soon thereafter, and Inglish and Simpson donated the original townsite, known as Bois d'Arc, as an inducement to settlement. Inglish also secured the town's first post office, which served an area of several hundred miles, including what is now Collin and Grayson counties. When Bois d'Arc became the Fannin county seat on January 26, 1843, the county extended into the Panhandle and Greer County, Oklahoma Territory; the area later became twenty Texas counties. Bois d'Arc was renamed Bonham on February 26, 1844, in honor of James B. Bonham, who died at the Alamo. By the early 1840s, C. C. Alexander of Cumberland County, Kentucky, established a business house to supply Fort Worth and nearby forts, and Bonham became a resting and supply base for homeseekers in northeastern Texas. During the Civil War the town was an agricultural center located at a strategic point near the state's northern border, though few people lived there between 1855 and 1870. Bonham was the site of Gen. Henry E. McCulloch's Confederate military headquarters for the northern subdistrict of Texas, and local merchants sold supplies to the government. After the Civil War an influx of settlers from the upper South increased the population and contributed to the town's educational, financial, and industrial development. Bonham incorporated on February 2, 1848, obtained a charter to incorporate land within a mile of the courthouse in 1873, and in 1990 operated under a charter granted in 1911.
The Masonic Female Institute, a young ladies' seminary, opened in 1855. Carlton College began in 1867, consolidated with Carr-Burdette College in Sherman in 1914, and affiliated with Texas Christian University in 1916. Fannin College for men opened in 1883. Public schools opened in 1890, and new brick buildings were constructed for both Black and White schools in 1928. Bonham Independent School District later absorbed thirty-two consolidated districts covering 230 square miles and five campuses. The Bonham News, the county's first newspaper, was founded in 1866 by B. Ober. The Fannin County National Bank opened in 1874, the Steger Opera House (built in 1890) brought touring companies of performers, and major church denominations were represented by 1900. Bonham women founded numerous service and cultural institutions, among them the Current Literature Club (1898), the Bonham Public Library (1901), and a Mother's Club that became affiliated with the national Parent-Teacher Association in 1924. Allen Memorial Hospital was built in 1903.
Bonham was a division point on the Texas and Pacific railroad in 1873. The Denison, Bonham and New Orleans branch of the Missouri, Kansas and Texas line was built from Bonham to Denison by 1887. By 1888 the town produced row crops including grain and cotton and had 117 businesses, three colleges, three papers, a furniture factory, a sawmill, gristmills, and gins. The Bonham Cotton Mill, once the largest west of the Mississippi, was chartered in 1900. The Bonham Free Kindergarten opened in 1907 to benefit mothers working in the mill. The mill was sold for profit in 1920 but retained its workforce and local manager. Work Projects Administration and Civilian Conservation Corps efforts during the Great Depression built the high school auditorium, gym, and other projects. World War II construction included a prisoner of war camp and Jones Airfield for pilot training (1941). Subsequently, row crops were replaced with pastures and small-grain farming, and Bonham farmers raised rabbits, poultry, beef, and dairy cattle. The Southwest Pump Company, General Cable plant, a Coca Cola bottling works, a cucumber-receiving station, and factories for ice, mattresses, brooms, mops, and ice cream employed local workers. In 1988 Bonham had 286 businesses, thirteen industries, a daily paper, an airport, an industrial park, the sixty-five-bed Northeast Medical Center, and a library facility completed in 1976. Bonham's population increased from 6,686 in 1990 to 9,990 in 2000, when it had 446 businesses.
Bonham is famous as the home of Sam (Samuel T.) Rayburn, national Democratic party leader and speaker of the House. The Sam Rayburn House and Sam Rayburn Library and the county museum of history are open to the public. Singer Roberta Dodd Crawford is also from Bonham. During the Texas Centennial celebration in 1936 federal funds were used to build a replica of Fort Inglish; a second replica was built in 1976. Bonham is the site of the annual Fannin County Fair. Bonham State Recreation Area is three miles southeast and Lake Bonham is located about three miles northeast of the community.