Oldest Oil Field in West

The superlative has not held still. In 1962 the bronze called Well No. 42, a mile north, the world's oldest continuously producing commercial well; one architectural survey says it stopped in 1988, while the state's own 1990s panel says it still trickled, and dates it 1882. The field itself is a geologist's oddity: its oil lies not in a porous dome but in fractures in the Pierre Shale, in a syncline, and drains into the bores by gravity. Florence refined it until its last refinery closed in 1936.

What the plaque says

This memorial is the property of the State of Colorado Oldest Oil Field in West In Florence and surrounding area was developed the first recognized oil field west of the Mississippi River, as a result of the discovery of oil by A. M. Cassidy in Fremont County in 1862. More than 1,300 wells, averaging 2,300 barrels per acre, have been drilled in this 14-square-miles area, including many within the city limits. One mile north is well No. 42, drilled in 1889, the oldest continuous commercial producing oil well in the world. It has produced more than 1,000,000 barrels. Erected by the State Historical Society of Colorado and the Florence Pioneer Day Association 1962

Where it stands

Worth the stop nearby

• Royal Gorge Bridge — 12 mi
  Built in six months in 1929 by a Texas promoter for people to pay to walk across, and still standing after a 2013 fire took 48 of the park's 52 buildings.

More markers nearby

• Rudd Cabin — 7.0 mi
• Garden Park — 11 mi