This document summarizes a routing protocol called the Virtual Grid Based Routing Protocol (VGRP) that aims to maximize the lifetime of wireless sensor networks by balancing the data traffic load evenly among sensor nodes. The VGRP splits the sensor field into a grid of equal sized sub-cells and uses clustering and chain techniques to collect sensed data. It is compared to the CFDASC routing protocol through simulation, and results show VGRP outperforms CFDASC in terms of network stability and load balancing. The document provides background on wireless sensor networks and reviews several related grid-based and load balancing routing protocols.