Sometimes it pays to know something of the history of America before commenting.
I would have assumed that many had read "The Vigilantes of Montana, or Popular Justice in the Rocky Mounains" by T. J. Dimsdale, published in 1866 in Virginia City, Montana Territory, one of the classics of western history. Dimsdale was there at the time and knew the people involved. The book is about the formation of the vigilantes, their capture of Plummer's road agents, and the hanging of the thieves and killers by a group of citizens of the Territory. The identity of the vigilantes, who cleaned up Montana, was secret for many years, but they are now known. Some were wealthy and influential men who contributed to the development of the future State. Nearly all were involved in mining, agriculture and ranching. The book has been reprinted many times, and is part of the "March of America Facsimile Series" which reproduced in full the most important historical works from the Fifteenth through the 20th centuries.

San Francisco was the site of another important vigilante group, and several books have been written about the lawless days and the vigilant actions by a group of prominent citizens.

Many other actions against the desperados of the west were taken by citizens who were forced to be their own police, judges, and juries.