From Long's earliest days as an artist his work has been revolutionary. His seminal early work A Line Made by Walking (1967) saw him alter the landscape by creating a straight line in long grass by walking repeatedly back and forth to leave the trace of his movement. These human gestures within nature and the mapped histories that they generate have been an enduring focus within his work. 

Long is also well known for his mud drawings, created with river mud and applied directly to gallery walls or onto sheets of paper. Regarding mud as 'a mixture of time, water and stone', Long embraces its physical properties and history as one of the first materials used to create art by early humans, assigning it a central importance in his work. For all his interventions in the natural landscape, his determination to use fragile materials in their rawest state suggests above all else the delicate beauty of the world, rather than its potential for exploitation.