The B5300 is a B road which runs for approximately twelve miles between the towns of Silloth and Maryport in the Allerdale borough of Cumbria, United Kingdom. From north to south, it passes through the villages of Blitterlees, Beckfoot, Mawbray, Dubmill, and Allonby. It runs through the Solway Coast Area of Outstanding Natural Beauty, passes close to the Salta Moss Site of Special Scientific Interest, Milefortlet 21, a Roman archaeological site, the salt pans, a remnant of the Solway plain's medieval saltmaking industry, and the village of Crosscanonby. It is an important route for carrying goods to and from Silloth docks and Maryport harbour. It is also the major road connecting smaller coastal settlements with Maryport and Silloth, from where other roads lead to Workington, Whitehaven, Wigton, and Carlisle. A short section of the road between Dubmill and Mawbray was closed in February 2019 due to coastal erosion, and reopened in June 2019.

Silloth is a port town and civil parish in Cumberland, Cumbria, England. Historically in the county of Cumberland, the town is an example of a Victorian seaside resort in the North of England.