Geo-partitioning is a technique used by CockroachDB to minimize latency in distributed databases. It allows control of data location at the row level, enabling users to keep customer data close to them and reducing the distance it needs to travel, thereby improving user experience. By applying geo-partitioning rules, P99 latency can be reduced from 400ms to under well under 40ms, a significant improvement that meets the 100ms rule for instantaneous interactions. This technique is particularly useful when dealing with applications running across multiple regions and users worldwide.