TURNER, Mont.—Thursday marks the 137th Opening Day of Major League Baseball and no fans in the lower 48 states are farther from the roar of the crowd than the 61 residents here.

As the crow flies, the Seattle Mariners are 648 miles away; Denver's Colorado Rockies, 650 miles. Earlier this year, residents discovered they were the answer to a trivia question locals had never thought to ask: What sorry town in the contiguous U.S. is farthest from a major league stadium?

Turner...