The road course in Watkins Glen, NY. Yes, really. Per the Elmira Star-Gazette, in an article previewing the race coming up this weekend:

While attendance totals are guarded because Watkins Glen is owned by publicly held International Speedway Corporation, track President Michael Printup hinted the crowd of more than 95,000 at last year’s race was a record for the event. It also marked the first time its seating capacity of 38,900 sold out.

Each year, the Glen race is bolstered by a large camping crowd, many of whom line the fences to watch the action. Those fans, who make the event a yearly pilgrimage, have helped keep Watkins Glen’s attendance at a steady 85,000-plus over the 30-year-span of the event.

That strong-and-getting-stronger attendance trend comes in stark contrast to virtually all the other tracks at which NASCAR races. ISC has spent $35 million on upgrades at Watkins Glen International over the past 11 years:

That investment has paid off for Watkins Glen, whose Sprint Cup event continues to thrive while others on the calendar, like the Brickyard 400 at Indianapolis Motor Speedway, have seen precipitous attendance declines. Once one of NASCAR’s premier events, attracting as many as 250,000 fans, crowd estimates from [two weekends ago] Indy race ranged from 35,000 to 50,000. That’s an all-time low in the 23-year history of the event.

Bristol Motor Speedway had its streak of 55 sellouts, which dated back to 1982, halted in 2010 when its capacity was at 160,000. The Tennessee oval races still rank among NASCAR’s more popular events, but the track is struggling to even sell half its seats today. Veteran reporters estimated April’s Food City 500 attracted between 65,000 and 70,000 fans.

With seats no longer being filled, many tracks have reduced their capacity significantly. Talladega Superspeedway, for example, reduced capacity from 143,000 in 2007 to 78,000. To better illustrate the changes, a recent USA Today story reported ISC and Speedway Motorsports Inc., who operate 20 of the 23 Sprint Cup Series tracks, have removed nearly a quarter of their capacity, or 475,000 seats, over the last five years.