It was on April 1, 1864 that Lassen County came into existence. It is interesting to note while Lassen County shares the date with April Fools, it is only fitting that its neighbor, the State of Nevada entered the union on Halloween, 1864. Also, notable on Halloween, Peter Lassen was born that day in 1800 in Denmark. It was on Valentine’s Day 1869, Susanville’s founder, and the first Provisional Governor of the Nevada Territory passed away from pneumonia at the age of 47.