191 Kolga is a large, dark main-belt asteroid that was discovered by German-American astronomer C. H. F. Peters on September 30, 1878, in Clinton, New York.

It is named after Kólga, the daughter of Ægir in Norse mythology.

[5] In 2009, Photometric observations of this asteroid were made at the Palmer Divide Observatory in Colorado Springs, Colorado.

The resulting light curve shows a synodic rotation period of 17.625 ± 0.004 hours with a brightness variation of 0.30 ± 0.03 in magnitude.

Previous independent studies produced inconsistent results that differ from this finding.