How to get the newest (last modified) directory [C#]

Non-recursive:

new DirectoryInfo(path).GetDirectories()
                       .OrderByDescending(d=>d.LastWriteTimeUtc).First();

Recursive:

new DirectoryInfo(path).GetDirectories("*", 
    SearchOption.AllDirectories).OrderByDescending(d=>d.LastWriteTimeUtc).First();