Udal law is a near-defunct Norse derived legal system, which is found in Shetland and Orkney, Scotland and in Manx law  at the Isle of Man. It is closely related to Odelsrett.
Udal law was codified by the kings Magnus I of Norway "the good" and Magnus VI of Norway "lawmender". The Treaty of Perth transferred the Outer Hebrides and Isle of Man to Scots law while Norse law and rule still applied for Shetland and Orkney.
Scottish Courts have intermittently acknowledged the supremacy of Udal law in property cases up to the present day. Major differences from Scots law include shore ownership rights, important for pipelines and cables.
Udal law generally holds sway in Shetland and Orkney, along with Scots law.