According to the newspaper, South Bend (Indiana) Tribune:

• Half of the world's recreational vehicles (RV's) are made in Elkhart, Indiana
• 80 per cent of the world's RV's are made in northern Indiana
• 40 companies make RV's in northern Indiana

https://www.southbendtribune.com/news/business/rv-industry-s-impact-in-northern-indiana-billion/article_3610e58e-9d66-53c9-bf1e-dbe78916858d.html

Elkhart is:

• 15 miles east of South Bend, Indiana, where Notre Dame University is located
• 110 miles east of Chicago, Illinois
• and 150 miles north of Indianapolis, Indiana
• only 15 miles from Interstate State 80 which goes between San Francisco on the     Pacific Ocean and New Jersey on the Atlantic Ocean.

https://www.mapquest.com/us/in/elkhart-282038198