Highest year: year after the 11th census (?)

Palermo Stone:  only 1 years remains on PS, and an unknown number of years on CF1
Turin Kinglist: 18 years

Manetho:

  Africanus: 63 years

  Eusebius does not mention this king

Mykerinos was the son of Khefren and Khamernebti I. He was married to his sister, Khamernebti II, with whom he had a son, Khunre, who died at young age.

He probably had two other wives, but their names are not known. One of these wives bore him a son, Shepseskaf, his successor, and another bore him a daughter, Khentkaus I, who may later have marriedUserkaf, the first king of the 5th Dynasty. 

According to the Turin King-list, his rule lasted for 18 or 28 years. The highest attested year from Mykerinos' reign refers to the 11th cattle count or the year after the 11th cattle count. With a biennal cattle census, Mykerinos would at least have ruled for 21 or 22 years, which, in view of the fact that his funerary monument was left unfinished when he died, would seem too long. The general concensus appears to be towards an 18 year reign and an irregular cattle census.

The Turin King-list also places another king between Khefren and Mykerinos, with an unknown number of years. This king may be the otherwise unattested Bakare, who may have been yet another son of Kheops’.

Contrary to Kheops and Khefren, Mykerinos was later seen as a benevolent and wise king. This may have been caused by the fact that his pyramid, built next to the pyramids of Kheops and Khefren at Giza, was slightly less than half the size of these two great pyramids. The mortuary temple built in front of his pyramid was completed, be it somewhat hastily, by his successor Shepseskaf.
 

Alabaster (calcite) head found in Mykerinos' Valley Temple in Giza (more...).

The pyramid of Mykerinos, with the pyramid of his father, Khefren, in the background.
The rubble lying to the right is what remains of one of the queen's pyramids.