Helpe Majeure is a river that runs through the Nord department in the Hauts-de-France region of France. It rises in the municipality of Ohain, with about a third of its watershed in Belgium, near the town of Momignies. The river initially marks the Franco-Belgian border as it flows north. Then it turns west and flows for 69 kilometres (43 mi) to its confluence north of Noyelles-sur-Sambre, as a southern tributary of the Sambre.