From the volvo site:

Considering you have to drive 100,000 miles to join, the Volvo High Mileage Club is surprisingly popular among Volvo owners. We've known for quite a while that Volvos have a reputation for longevity, which speaks well for the Volvo engineers and craftspeople that design and build our cars. And our dedication to automotive safety and quality of construction is equally strong. So a few years ago, we introduced the Volvo High Mileage Club to recognize owners who have driven their Volvos more than 100,000 miles. New members receive an attractive grille medallion and letter of verification, with ongoing recognition for every additional 100,000 miles they drive.

2,000,000 Miles and Counting
Perhaps the single most stunning example of legendary Volvo durability is the shiny red 1966 Volvo P1800 owned by Irv Gordon. So far it has been driven a world-record-breaking 2,000,000 miles and counting.

How to Join
It couldn’t be easier. Provided your Volvo is legally registered and the odometer reads at least 100,000 miles, you’re just one call away from becoming a member of the High Mileage Club. Simply call the Volvo Personal Shopper at 1-800-550-5658 for a registration form.