A comment in a Slashdot article lead me to iploc.org, specifically Country names zone which lets you get the country for a given IP address over DNS.

I wrapped it in a bash function… throw this at the end of your .bashrc:

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geo() { dig +short TXT `echo $1 | \
 awk -F. '{print $4"."$3"."$2"."$1".cc.iploc.org"}'`;}

and you can get geo information from the command line:

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$ geo 204.187.154.1
"CA"