North Dakota Oil Fields at Night, July 2015

The Bakken Formation underlies much of western North Dakota and became the center of a major U.S. oil boom beginning around 2008, driven by advances in horizontal drilling and hydraulic fracturing. Scattered flares and site lighting across the prairie here mark well pads, pumpjacks, and gas-processing equipment that typically run continuously rather than on daytime schedules. By the mid-2010s, the formation had pushed North Dakota past California to become the second-largest oil-producing state in the country, behind only Texas. Many wells in the region also burn off natural gas through flaring when pipeline capacity isn't available to capture it, a practice that accounts for much of the glow visible on the horizon in oil-producing counties like Dunn and McKenzie.

Photo taken in July 2015.