Beauregard Parish Courthouse, National Register courthouse in DeRidder, Louisiana.

The Beauregard Parish Courthouse in DeRidder is an early 20th-century government building located at 201 West 1st Street. Its architectural style reflects the design standards for public buildings in the American South during that period.

Beauregard Parish was carved out of Imperial Calcasieu Parish, and its new police jury bought a building and adjoining land from the First Baptist Church after the Hudson River Lumber Company donated a tract to DeRidder. Stevens-Nelson of New Orleans designed the courthouse and jail, Falls City Construction Company won the contract in September 1913, and both were finished in 1915 for $168,000. The courthouse joined the National Register of Historic Places on 22 September 1983.

The courthouse's notoriety comes from a trial that ended in two hangings at the adjacent Beauregard Parish Jail, which gave the jail the nickname "Hanging Jail"; that notoriety faded after the hanging of March 9, 1928. Today the renovated jail is open for weekday tours, with occasional nighttime lantern tours and a haunted house around Halloween.

The courthouse stands in DeRidder, the parish seat, and the old jail beside it can be toured on weekdays, with occasional lantern tours at night and a haunted house around Halloween. The tunnel between the two buildings is blocked off and holds standing water, so it cannot be walked. Renovation work has covered a third courtroom, ADA access, elevators, sewer lines, the courtyard and sidewalks.

An illuminated underground tunnel once connected the courthouse to the adjacent jail, allowing secure prisoner transport for court proceedings. This functional passage is no longer operational but remains a notable feature of the building's history.