XElement.GetNamespaceOfPrefix gets the namespace associated with a particular prefix for this XElement.
using System; using System.Linq; using System.Xml.Linq; using System.Collections; using System.Collections.Generic; public class MainClass{ public static void Main(){ XElement xmlTree = XElement.Parse("<Root xmlns:aw='http://www.domain.com'/>"); XNamespace awNamespace = xmlTree.GetNamespaceOfPrefix("aw"); Console.WriteLine("Namespace: {0}", awNamespace); } }