Mandiraja (Javanese : ꦩꦤ꧀ꦢꦶꦫꦗ) is a district (kecamatan) in Banjarnegara Regency, Central Java, Indonesia.

The distance from Mandiraja District to the capital of the Banjarnegara Regency is about 21 km, and is located at an altitude of 132 metres above sea level.

Mandiraja has a tropical climate, with humidity ranging between +50-90%, peaking in December to March, with the lowest levels in July to September.

[1] Mandiraja has a gender difference ratio of 96.22%, and an annual population growth of 1.47% in 2023.

In addition, there is a traditional musical instrument, the calung, a kind of idiophone made from bamboo, which is played by hitting the blades or segment.