Marshall, Harrison County seat, quickly rose to prominence by 1850, a mere eight years after the county’s formal organization. With a population of 1,189 citizens, it was considered the fourth largest town in the state. Harrison County’s thriving plantation economy created a class of wealthy land and slave owners and by 1860 there were more slaves in Harrison than any other county in Texas. The county’s first courthouse, completed the same year, expressed the town’s affluence with its elegant, Neoclassical façade and square-plan antebellum charm.

County citizens were partial to the political arena, thus lively public discussions involving county politics and economics were a common sight in and around the courthouse square. Following the end of the Civil War and throughout Reconstruction, Marshall’s population increased over 100% and by 1887 a new, larger courthouse was required to manage the increase in county business. The antebellum charmer was demolished, replaced by a handsome, three-story Italianate structure featuring St. Louis pressed-brick, sandstone trim, and a 175-foot tall tower, and completed in 1889. On June 7, 1899, the impressive courthouse was gutted by fire.

Within weeks of the disaster the county commissioners court drafted a plan to replace the ruins with a new courthouse, hiring one of the state’s preeminent architects of the late 19^th century to prepare the design. J. Riely Gordon, already a veteran of public works and known for his Romanesque Revival monuments in which polychromatic materials, massive arches, multiple flanking and multi-storied towers were feature characteristics, employed the best of his creative design skills to devise a courthouse to rival justice centers across the state. Aware of the new influences dominating architectural design at the turn of the century, Gordon incorporated Classical Revival and Beaux Arts details in his dramatic reimagining of a Harrison County courthouse, creating one of the most stylistic historic public buildings surviving in Texas today. The courthouse, with National Register listing, expresses both architectural and historical significance with its landmark status. The Neo-Italian Renaissance Revival monument features a dramatic interior rotunda, a façade of locally-fired buff-colored brick, a rusticated base of pink quarry-faced granite (a material and architectural element reminiscent of Gordon’s Richardsonian days, and similar to that found on the State Capitol), and Roman arches. A central octagonal dome rises above the structure, accented with bronze plating, four clock faces, and a dozen bronze eagles. At its apex rests a lantern base supporting the statue of the Goddess of Justice with scales. The original timepiece, an E. Howard Round Top No. 2, featured chimes operated by two hundred pounds of weights which were hand-cranked to the top of the tower every eight days.

Completed in 1901, the elaborately detailed design began requiring a steady stream of repairs and alterations through 1925. Perhaps the most dramatic change involved detaching the entire east portico, moving it over twenty feet, then in-filling the gap between the existing building and the relocated portico with material relevant to the original design. By 1948, metal repair work included replacing the arm, wing and scales of the Justice figure and replacing missing wings on the eagles. During a 1965 restoration, the wings on the Justice figure were reoriented to point downward in a misguided effort to reduce “wind friction” wear but the wings were returned to their original upright position during the 2009 restoration.

By the turn of the 20^th century, the Harrison County courthouse, in need of a complete renovation and restoration, no longer served as central location for county offices. A modern courthouse had already alleviated its responsibilities completely by 1998 and the historic courthouse had begun to serve as county museum. The courthouse’s latest restoration, courtesy of significant funding from the Texas Historic Courthouse Preservation Program, involved Harrison County citizens’ participation as well as state assistance. The twelve eagles adorning the dome perimeter received their own unique restoration aid from the Eagles for Eagles, a program driven by thirteen thousand Harrison County students who competed in raising money by collecting quarters to assist in the replication of their “adopted” eagle. The program was a success and by May 13, 2004, students were celebrating the reinstallation of the final eagle around the dome. “That’s our eagle,” chair of the Harrison County Historical Commission heard students say, solid evidence that a renewed connection between citizens and the historic public square had been made.

Today, the Harrison County Historical Museum occupies several wings of the courthouse, featuring exhibits ranging from the Native American Caddo culture to the history of the Wiley College. The museum's collection includes thousands of artifacts and has an extensive photographic and text archive partially maintained by a genealogical society. Notable pieces housed in the museum include; an Inaugural ball gown worn by Lady Bird Johnson and an accompanying suit worn by Lyndon Johnson, the Emmy Bill Moyers won for his documentary Marshall, Texas: Marshall, Texas, and George Foreman's world championship belt.

In addition to the Courthouse and the Research Center, the museum has opened a military museum in Memorial City Hall Performance Center (MCHPC) entitled "Service and Sacrifice: Harrison County at War ''. This is a permanent exhibit and includes 1700 sq. ft. of history. Also in MCHPC is a set of rotating exhibit areas on the second floor.

Finally, the museum also has a North Gallery at the Marshall Mercantile on North Washington St. in Marshall.