The Northumberland County Courthouse (207 Market Street) was listed on the National Register of Historic Places in 1974. Portions of the content on this web page were adapted from a copy of the original nomination document. 
The present appearance of the Northumberland County Courthouse does not differ substantially from its original appearance. The Northumberland County Courthouse is a three-story, brick building. A three-story wing, which was added in 1911, extends to the east. The front facade of the building has three arched doors surrounded by massive stone work and topped by a stone balcony. This stone work and the striking corner quoins of the building were probably made of brownstone quarried near Hummelstown, Pennsylvania. Second and third story windows on the front facade are of Italianate style, topped by dripstone. Windows on other elevations of the building are two stories in height and contain small windowpanes arranged in a crisscross pattern. All second-story windows are recessed. The cornice on the front is bracketed; elsewhere on the building the cornices are dentiled.
The clock tower remains as originally built except for some ornamentation at its base. Its dome is copper (now painted). The clock was built by E. Howard of Boston and installed in 1872. The bell in the tower was presented to the citizens of Sunbury by Simon Cameron, (Lincoln's Secretary of War), a native of the area.
In the interior, a marble tiled floor on the first floor is an original feature. A room on the second floor of the addition has a coffered ceiling of wood in squares, with outlined designs in color.
Alterations to the building have not been extensive. The first-floor windows originally had small panes of glass; nearly all these panes have been replaced. The ornaments originally on the four extended corners of the building have been removed. In 1911, the transverse hall was made into rooms on either side of the central hall, and the doorways to the east and west became windows. They retain their original massive stone door frames on the exterior.
The Northumberland County Courthouse is a fine example of the 19th century Romanesque architecture. No architect was hired to design this building; in 1865 the county commissioners decided to copy the Lycoming County Courthouse built in 1861 and designed by Samuel Sloan, a Philadelphia architect of some note. He also designed the Episcopal Hospital in Philadelphia and the Philadelphia Savings Fund Society. The Northumberland County Courthouse is practically identical with the Old Lycoming County Courthouse, which was razed in 1969.
The Northumberland County Courthouse is significant because it has the massiveness and solidity of Romanesque masonry that became lost to architectural design when steel girders came into use. This type of public building is becoming more scarce throughout the country.
The political and historic significance of the Northumberland County Courthouse is greater than that of any other extant building in Northumberland County. It is a symbol of the life of the county in an age of newly discovered wealth and population increase, at the time of the Civil War. The new wealth created by the mining of anthracite coal, railroads, and industry, was accompanied by poverty and unrest, which provided the climate for the Mollie Maguire murders which shook the area for years. The Northumberland County Courthouse was the scene of the trial and conviction of the last "Mollie," Peter McManus, for murder in 1878. The Northumberland County Courthouse was also the scene of ejectment suits which settled boundary disputes, thus bringing stability to the area. The Northumberland County Courthouse is, therefore, a bridge linking the past political and legal history of Northumberland County with that of the present. Destruction of the building will be damaging to that continuity of county history.
Everts and Stewart, "History of Northumberland County," publisher - Everts and Stewart, 1876.
Bell, Herbert C., "History of Northumberland County," Brown Runk and Co., publisher, 1891.