In order, no and yes.
Clark County is named for a now-obscure U.S. senator from, believe it or not, Montana. You're thinking of someone else. "Handsome" Ed Clark (1871-1946), the son of a Storey County sheriff, had a lasting influence on southern Nevada, including making it the Democratic Party’s lone stronghold in the Silver State. As A.D. Hopkins writes in The First 100: Portraits of Men and Women Who Shaped Las Vegas:
"He seemed always to know what needed to be done and how to do it, then did it before anybody else thought of it. When Las Vegas became the railhead serving rich mines to the north, Clark hauled the freight. When the time came to break away from Lincoln County, Clark did much of the political engineering. He ran Las Vegas' first bank, its first telephone company, and its first power company. He helped bring Hoover Dam to reality and, perhaps most important, obtained for Nevada a share of the electricity it would generate."
Clark entered the cattle business at age 17, later co-founding the Ed W. Clark Forwarding Co., which moved supplies between western Utah farms and the nearest railhead. A man of foresight, Clark ran for -- and won -- the office of treasurer of newly formed Clark County in 1909. He also joined the board of First State Bank, later ascending to its presidency. He bought into nascent Consolidated Power & Telephone Co., which evolved into Nevada Power and Sprint of Nevada (now Embarq). He spent a quarter-century lobbying for what would eventually become Boulder Dam -- now Hoover Dam -- and his Southern Nevada Power was the first utility to distribute the electricity the dam generated.
His influence in Democratic circles was strong enough to persuade President Franklin Delano Roosevelt to re-route his Hoover Dam dedication tour through Las Vegas and even up to Mount Charleston. Clark was also able to bring home the bacon in the form of munitions plants that were the germ of the City of Henderson.
A lifelong bachelor, Handsome Ed didn’t leave any heirs, though there were allegations of a son fathered out of wedlock. But at least one direct descendant can still be found. If you go to Clark County Auto Parts, you’ll be dealing with one of Ed Clark’s original businesses, still in operation at 505 S. Main St., in the heart of the power broker’s old stomping grounds.
In the case of James "Big Jim" Cashman (1894-1962), he was indeed the namesake of Cashman Field, built in 1983. In the prototypical example of the "Vegas dream," Cashman hit town in 1904 with but a dime to his name, or so family lore -- as passed on to A.D. Hopkins (to whom we are indebted for these narratives) has it. He parlayed waiting tables and washing dishes into a lunch-counter concession of his own. It ended badly, though, when Cashman’s partner blew all their money.
Broke again, Big Jim took odd jobs, one of which eventually grew into his own telephone-line-repair company, followed by a rustic taxicab service, then a trucking company. To facilitate the movement of ore from Arizona to the railhead, Cashman launched his own ferry. Since there were no auto-repair shops on the St. George-to-SoCal route, he opened one in Searchlight, which eventually grew into a car dealership. And so on. Wherever he sensed a vacuum, Cashman was quick to fill it.
The Cashman achievement for which Californians and Las Vegans alike are probably most grateful is his brokering of a joint venture between Clark and San Bernardino counties to bust through the mountains in 1927 and build the road that would evolve over the decades into I-15. Airplane and boat tours, construction equipment, building Helldorado Village … Big Jim’s reach befit his name, which soon adorned the original Cashman Field (c. 1948), carved out of the same hillside the current Cashman Field adorns.
The mogul successfully butted heads with union leaders who picketed his house and later took credit for burning down his auto business. (Two of his adversaries later came to bad ends, but not by Cashman’s hand.) Perhaps as a form of revenge, Cashman was the prime mover behind the right-to-work law that chagrins union organizers in Nevada to this day.
"His nickname sounds like that of an old-time political boss, bullying people till he got his way," Hopkins writes. "In fact, Big Jim was the opposite. He didn't drive people, but led them. His tool kit was full of charm, humor, and a logic-defying insistence that everything was FUN."
So "Big Jim" Cashman gets his rightful due while "Handsome Ed" Clark was somewhat shortchanged. But, considering the latter’s integral role in the growth of Clark County, if it wasn’t named after him, it probably should have been.