Clark County, NV
History
Clark county was formed by the Nevada Legislature by splitting off a portion of Lincoln County on February 5, 1909,and came into existence on July 1, 1909.Much of the county was originally part of Pah-Ute County, Arizona Territory before Nevada became a state. The county was named for William Andrews Clark, a Montana copper magnate and U.S. Senator.http://en.wikipedia.org/wiki/Clark_County,_Nevada
Modern Day Adjacent Counties
Lincoln County - northNye County - west
Inyo County, California - southwest
San Bernardino County, California - south
Mohave County, Arizona - east