Can we know from what page user went to 404?

Raygun reports about all 404 (page not found) errors. This is great - but unfortunately it tells me only where user wanted to go, but not where from. In example, I can get a 404 error saying that user wanted to get to "www.myapp.com/login.aspx", but this page doesn't exist (but there is "www.myapp.com/account/login.aspx") which means that I have somewhere a wrong link, wrong redirection etc. But in this case Raygun doesn't tell me where this error occurred from.

Is there a way do display urlReferrer /HTTP_REFERRER or any other way to find out the previous page?

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