I know LVC did not appear in Once Upon a Time in the West, however this location is part of the La Calahorra Train Station, and it would be a shame not to document it.
Instead of reusing the Mini Hollywood location built for For a Few Dollars More and used again in The Good, The Bad, and The Ugly, Sergio Leone chose to build a new location for Once Upon a Time in the West outside of the La Calahorra train station near Guadix.
Town as it appeared in the film
Like "El Paso", The town of Flagstone was a mammoth location. unfortunately unlike three other spaghetti western towns built at the time, this location was not preserved by turning it into a tourist location. As is stands now, only the brick buildings remain. The main building used in the film, The Flagstone Saloon, has been modified into a barn.
Then and now - 45 years apart
Additional pictures of the town's remains below. Click to enlarge.
I also visited the site of the hanging arch in the US, which you can check out here.