The LEACH protocol remains a foundational clustering algorithm for wireless sensor networks, yet its random cluster head selection leads to uneven energy consumption and premature network degradation. Despite numerous modifications, no existing variant incorporates a spatially deterministic dual-layer grid hierarchy for structured area management. This paper proposes G2LEACH, which introduces micro-area and Grid of Head Areas (GHA) structures to enable geometrically controlled cluster head placement. Six algorithm configurations are evaluated through extensive simulations (1200 nodes, 100 independent runs) in two deployment scenarios. In the 1000 × 1000 m scenario, G2LEACH achieves a 955% improvement in the Half Nodes Alive metric and extends total network lifetime by 75%. In the compact 100 × 100 m scenario, the First Node Dead metric improves by 87%. The results confirm that spatially structured clustering significantly enhances network longevity and coverage uniformity.