How to get visitor location ( country, state and city ) using ASP.NET

First, get the IP address of the visitor using Request.ServerVariables("REMOTE_ADDR"). Bear in mind that the visitor could be using a proxy server in which case the IP address may not be their actual IP address. For the proxy case, you can check if Request.ServerVariables("HTTP_X_FORWARDED_FOR") contains a value. This will be the actual IP address if the proxy server is not an anonymous proxy server.

Then you have 2 options, using a web service or querying data from your own database. Either way, you will need data which can match an IP address of the visitor to their country, state and city.