The Nevada-California-Oregon Railroad (NCO) did a great deal for the development of eastern Lassen County. As a result, a number of communities sprang up, some a mere outpost and others a bit more substantial. However, like the railroad, many in time would fade into oblivion.

In 1899, the (NCO) established a station in Secret Valley. Those residents thought it would become a major shipping point on the NCO, like its recent predecessor, Amedee, but that did not occur. This did not prevent James Sellick from constructing a two-story hotel at the Karlo Station that summer. The station was named for the DeCarlow Brothers—Alonzo Metardus (1868-1949), Charles William, and Walter Henry (1859-1949). Charles W. DeCarlow was the first member of the trio to arrive in Secret Valley when, in 1889, he and H.F. Buhrmeister purchased 200 acres from D.C. Hyer for $2,400. When the station was established in August 1899, there was confusion as to how to spell it. The locals spelled it Carlo, but the railroad clearly indicated it was K-A-R-L-O. The Lassen Advocate noted: “The management of that road seems to have a liking for short names and odd spellings following in the wake of the Postal Department in this respect.”  It is interesting to note the next station the railroad  established was named Termo.