Yes, at the NIST. It’s a platinum-iridium bar, and has been directly refered to in several court decisions.
Could you please hint me to some of these court decisions?
And the NIST seems to hide its platinum-iridium bar, while bragging with other, more accurate definitions and measurements:
In 1960, the international scientific community adopted a new standard of length, replacing the old platinum-iridium meter bar with a wavelength of a specific frequency of visible light. (An Institute invention of the 1940s was influential in demonstrating the precision and practicality of a wavelength standard of length.) The new measure was based on atomic properties and could be reproduced with great accuracy, whereas the meter bar could be damaged or change over time. Shortly thereafter, NIST designed and built one of the first fully automated measuring machines, an interferometer (which used wavelengths of light as the unit of measure) for calibrating the intervals on length scales. It reduced calibration time and cost by a factor of 10. Before the end of the decade, a new method of stabilizing lasers was discovered by NIST scientists, yielding a 1,000-fold improvement in reproducing measurements made with an interferometer.