SgmlReader is a .NET library for parsing HTML/SGML files using the XmlReader API
SgmlReader is a .NET XmlReader implementation customized for reading a wide variety of SGML documents, including HTML. Because it is based on XmlReader, one of the lowest level .NET tools for working with XML documents, you can then use a wide variety of tools on top of it to actually read the documents, such as XmlDocument and LINQ to XML.
See https://github.com/MindTouch/SGMLReader for more information.