Sites like WallpaperCave and 4KWallpapers offer the macOS Sierra mountain scene in 1920x1080, 4K, and 5K formats.

Developers often maintain repositories like foxt/macOS-Wallpapers which contain the full history of Apple's default desktop pictures.

Threads on subreddits like r/apple often share direct links to high-quality versions of every default Mac wallpaper.

If you are looking to download this specific resolution, several platforms host collections of Apple's stock wallpapers:

Lone Pine Peak in the Eastern Sierras, near the town of Lone Pine.

The search term "1920x1080 Os X Sierra Wallpaper 38 Wallpaper Av..." appears to be a common search query string for finding high-definition desktop backgrounds originally included with . The Official macOS Sierra Wallpaper