[1] Working largely outside the confines of the traditional art spaces of galleries and museums, Heizer has redefined sculpture in terms of size, mass, gesture, and process.

A pioneer of 20th-century land art or Earthworks movement, he is widely recognized for sculptures and environmental structures made with earth-moving equipment, which he began creating in the American West in 1967.

[4] The paintings that would follow, characterized by non-traditionally shaped canvases, demonstrate Heizer's early exploration of positive and negative forms; such harmonies of presence and absence, matter and space, are essential to his art.

[8] For Displaced/Replaced Mass (1969/1977), later installed outside the Marina del Rey, California, home of Roy and Carol Doumani, he planted four granite boulders of different sizes from the High Sierra into lid-less concrete boxes in the earth so that the tops of the rocks are roughly level with the ground.

[9] For a 1982 work at the former IBM Building in New York, Heizer sheared off the top of a large rock and cut grooves into the surface before setting it on supports hidden within a stainless steel structure.

[9] Commissioned by the president of the Ottawa Silica Company, the Effigy Tumuli earthwork in Illinois is composed of five abstract animal earthworks reclaiming the site of an abandoned surface coal mine along the Illinois River; the shapes (1983–85)—a frog, a water strider, a catfish, a turtle, and a snake—reflect the environment of the site, which overlooks the river.

It details the making of the sculpture as it relates to Heizer's career while portraying the boulder's 105-mile journey through Los Angeles and the public's reaction to its installation.

[16][17] In July 2015, President Barack Obama signed a proclamation (using his authority under the Antiquities Act of 1906) creating the Basin and Range National Monument on 704,000 acres in Lincoln and Nye counties, an area including Heizer's City.