Californiulus yosemitensis is a species of cylindrical millipede in the family Paeromopodidae that is found in western North America: predominantly in the Sierra Nevada of California but also extending into southeastern Oregon and parts of Nevada.

Adult C. yosemitensis reach lengths of up to 11 cm (4.3 in) and up to 80 body segments.

[1][2] Californiulus yosemitensis occurs from extreme southwest Oregon to Kern County, California, with populations in the Warner Mountains, Cascade Range, and Sierra Nevada.

In certain parts of Yosemite National Park C. yosemitensis co-occurs with Paeromopus paniculus, a larger member of the family Paeromopodidae.

The holotype specimen was collected in Yosemite in 1931 and is stored in the National Museum of Natural History in Washington, D.C.[2] Chamberlin later described two species Klansolus mononus and K. obscurans, which were subsequently determined to be the same species as, and thus taxonomic synonyms of, C.