Last account activity shows you information about recent activity in your mail. Recent activity includes any time that your mail was accessed using a regular web browser, a POP1 client, a mobile device, a third-party application etc. We'll list the IP address that accessed your mail, the associated location, as well as the time and date.
To see your account activity, click the Details link next to the Last account activity line at the bottom of any Gmail page.
How to understand this data
If you're concerned about unauthorized access to your mail, you'll be able to use the data in the 'Access type' column to find out if and when someone accessed your mail. For instance, if the column shows any POP access, but you don't use POP to collect your mail, it may be a sign that your account has been compromised.
Location (IP address)
In this column we list the last 10 IP addresses your mail was accessed from, and the associated locations.