There is a standard Marketo field called Inferred Country which will perform a reverse IP lookup of the lead's first recorded web visit. The only caveat with the use of this field is if someone is not in their typical workplace or traveling then the Country data would not be all that accurate.
I hope this helps!
yes - that's the field we would want to use, and we're aware about the issue with travel - however, I am being told that it is not possible to pre-fill the Country field on the form using this IP lookup Country value - this is my question to the group - is it possible, or does it require the form to be submitted before the value becomes available?
It is definitely not possible to use the Inferred Country when the lead is on their first anonymous pageview, because the field is not attached to their record yet.
It is definitely possible to use a third-party tool to perform an IP-to-country guesstimate and use that to fill in Country, though you should definitely let the lead override it (since they are the authority).
A long time back I showed how to use browser location services and IP lookup services (2 different examples that can be used together for super-powered detection) if you search the Community.