Demurrage (Lat. demoror, to delay), in maritime law, the detention of a vessel beyond the time allowed by the charter party (or by custom if there is no special contract) for loading or unloading or sailing; also the compensation paid or damages claimed for such detention. It is usually stipulated in the contract between the owner of the ship and the freighter that the ship shall not be detained beyond a certain time for the loading or delivery of goods, or for sailing. If there is no such stipulation, the time is fixed by usage, and called lay days. The claim for demurrage is reciprocal, by the owner against the freighter, and' by the freighter against the owner; the latter case being, however, only for delay in sailing. Demurrage is allowed only for voluntary detention, and not for any accidental delay; as, if a vessel is detained for a cargo over the stipulated time, and after sailing is driven back by a storm, which would have been avoided if she had started at the time appointed, no damages are allowed for the incidental delay. Yet it would perhaps be otherwise if by the detention a further delay is caused by anything which could be foreseen, as a periodical wind, or the freezing up of a harbor, or the like.

In inland transportation, where the latter cause of delay most frequently occurs, as upon rivers or canals, the rule is that the carrier is not responsible for the delay when there has been no fault on his part, but is entitled to deliver the cargo after the breaking up of winter, and earn the entire freight; or if the freighter elect to take the. goods at the place of detention, he must pay pro rata itineris. But if there has been voluntary delay by either party, in consequence of which the vessel is frozen up by the coming on of winter, he is responsible for damages; but the measure of such damages would not be according to the rule of demurrage in respect to sea vessels.