Boulder is a city located in the United States. While it shares its name with a geological term, the specific geographical location of this municipality is not detailed in the provided source material.
In geology, a boulder is defined as a rock fragment with a diameter greater than 25.6 cm (10.1 inches). These fragments are distinguished from smaller pieces known as cobbles and pebbles. While some boulders may be small enough to be moved or rolled by hand, others are extremely massive; in common usage, the term typically refers to rocks too large for a person to move.