Engesser Pass is likely the most remote trail in Arizona based on travel distance to the nearest human habitation. Engesser Pass traverses the midsection of the beautifully rugged Kofa National Wildlife Refuge, which covers over 1,000 square miles with not a single human inhabitant. The 2,000 square miles of the Yuma Proving Grounds cradle the bottom of the refuge. No one lives there either since the Proving Ground is where the Marines test things that explode. Approximately 3,000 square miles of uninhabited BLM land lie east of the refuge. That is 6,000 square miles. Four states, Hawaii, Rhode Island, Delaware, and Connecticut, are smaller. In all that space, no human resides full-time. No light bulb burns at night. Very few roads exist. And in the middle of all that splendid remoteness is Engesser Pass. When traveled east to west, Engesser Pass begins as an easy two-track on a ridgeline above the vast saguaro-studded Palomas Plain to the east. Mountain ranges sawtooth the horizon in every direction, near and far. Ocotillos reach skyward, flaming red flowers on the ends of their long tendril shafts. Thickets of thorny silver cholla scatter their pin cushion droppings to painfully attach to the unwary. To the west looms the multi-hued sawtoothed Kofa Mountains. Before long, Engesser begins its slow rise to the mountain pass that gives the trail its name. Cutting through the ruggedly beautiful Kofa Mountains, the view westward from the pass is unsurpassed. The trail dives steeply to join Engesser Wash, brushy and sandy, as it slolams down and out of the mountains. Turning northward, Engesser parallels the colorful west side of the ancient volcanic Kofas. To the west across the broad King Valley lies the Castle Dome Mountains, the round spire of Castle Dome clearly identifiable. Engesser Pass ends near the King of Arizona mine, whose initials gave became the name of the area. It is far more likely that you will see a desert bighorn sheep, the reason for the refuge's existence, or perhaps a tiny kit fox than it is you'll see another human on your traverse of Engesser Pass. Solitude. Beauty. Good wheeling. All fine reasons to explore one of Arizona's most remote trails.