Local search systems must determine WHERE to search before retrieving results. We present OmniQUM, a fine-tuned 7B model for generative location disambiguation: given a query and geo-coordinates, it produces a disambiguated location target and bounding box decision in a single pass. Unlike NER + gazetteer pipelines, it jointly reasons over query intent and geographic context. We train across 14 locales and 7 languages with a failure-driven agentic pipeline generating targeted samples iteratively. We introduce expanding donut retrieval, sampling candidates from concentric, slightly overlapping rings to improve recall over naive bounding box retrieval. On 52K queries reflecting real traffic distribution, we achieve F1 0.94 on location disambiguation and 32.7% retrieval recall improvement, surfacing 86K additional relevant POIs. Deployed with vLLM and bf16 on dual GPUs, we achieve sub-150ms TM95 latency at 0.12× baseline cost, with 7–38% cache hit rates.